For other uses of the name Jason, see Jason (disambiguation).
|Champion of Juno|
|Hero of Olympus|
|Son of Jupiter|
|Family||Jupiter (father) |
Ms. Grace (mother)
Thalia Grace (sister)
|Affiliation|| Olympians |
|Weapons|| Ivlivs (destroyed) |
|Home|| Camp Jupiter |
Camp Half-Blood (The Lost Hero)
|Appearances|| The Lost Hero |
The Son of Neptune (mentioned)
The Demigod Diaries
The Mark of Athena
The Blood of Olympus
|Quests||Quest to Save Hera|
|“||I'm the son of Jupiter! I'm a child of Rome, consul to demigods, praetor of the First Legion. I slew the Trojan sea monster, I toppled the black throne of Kronos and and destroyed the Titan Krios with my own hands. And now I'm going to destroy you, Porphyrion, and feed you to your own wolves.||”|
Jason Grace is one of the main protagonists of the second Camp Half-Blood series, The Heroes of Olympus. He is the son of Jupiter and Ms. Grace and the younger brother of Thalia Grace. He was a praetor at Camp Jupiter until he gave his rank to Frank Zhang; he is the current counselor of Cabin One at Camp Half-Blood.
Jason was born on July 1st and is the son of Jupiter, the Roman aspect of Zeus, and a mortal actress with the last name of Grace. He was born seven years after Zeus fathered Thalia in his Greek aspect. Because his father had consecutively sired two children with his mother, Juno, the Roman form of Hera, was made Jason's guardian to placate the indignant goddess and Jupiter went even as far as to name his newborn son after his wife's favorite hero, Jason.
When Jason was two years old, Juno commanded his mother to bring him to the Wolf House. It was there that he was separated from his mother and sister to be initiated by Lupa in the ways of Rome. After training for some time under the wolf goddess, he journeyed to Camp Jupiter where he was raised in the lifestyle of the Roman Legion. Eventually, Jason was inducted into the Fifth Cohort and would bring a restored sense of honor to the disgraced contingent. This would culminate when he was made praetor, the co-commander of the entire legion.
Jason wakes up on a bus belonging to the Wilderness School holding hands with a girl he doesn't even know. He finds that he has no memory of even going to the school or having a best friend named Leo and a girlfriend named Piper. Gleeson Hedge, his supposed gym teacher and satyr protector (though Jason doesn't know that yet), tells him that he's never seen him before today and that the Mist has been manipulated to make everyone think that they know him. He also reveals that he, Piper, and Leo are demigods and that an extraction team (Annabeth and Butch) is coming to get Piper and Leo to camp along with an unknown "special package", which turns out to be Jason.
When, an unnaturally powerful storm arrives, Dylan, revealed himself to be a Ventus or Venti,a storm spirit, (Greek form anemoi). Jason instinctively took out his gold coin, flipped it, and it became a well balanced sword made of Imperial Gold.While he and Piper fought off Dylan, Hedge (who revealed himself to be a middle aged satyr) climbed down the canyon wall to retrieve Leo when he was thrown down. Jason also survived a lightning bolt which Dylan attacked him with that could have killed twenty men, blowing off his shoe. Piper is thrown off the sky-walk and Jason jumps after her, discovering that he can manipulate air. After a long battle, Dylan takes Hedge away and leaves Leo, Jason, and Piper on the canyon sky-walk. Just then two half-bloods arrive on a chariot pulled by pegasi; a guy named Butch, son of Iris, and Annabeth, daughter of Athena. When Annabeth and Butch notice Jason only has one shoe on (as the other one was blasted into bits by the lightning bolt), Butch tells them that Annabeth had a vision that a boy with one shoe would help her find one of the campers, who has been missing for three days, her boyfriend Percy Jackson.
After they arrive at Camp Half-Blood, Annabeth gives Jason and Piper a tour of the camp. Jason then meets Chiron who immediately realizes who Jason is by speaking in Latin, to which he responds in Latin. Afterwards they find out Hera is in danger, and Jason must lead a quest in order to save her. Jason reveals his godly parent through a lightning bolt, showing that he is a son of Jupiter. He chooses Piper, who is now claimed by Aphrodite, the goddess of love, and Leo, who was claimed by Hephaestus when they got to Camp Half-blood, to go with him on his quest. Jason also receives a Prophecy saying that he must beware the earth, possibly because Gaea, the Earth, is his enemy and that she bears arms to the Doors of Death.After they embark upon their quest, they meet king Boreas, who tells them to go to Chicago, the windy city.There they meet Medea, a mortal who was supposed to have died more than 3000 years ago. Later, Jason and his companions meet another mortal who was supposed to have died millennia ago. King Midas, the king who wished for the golden touch, then learned to bring back people from their golden state with running water. Midas quickly turns Piper and Leo into gold statues. Jason retaliates by summoning a lightning bolt to destroy Midas.
They head to Pike's Peak to meet Aeolus, master of the winds. Then Piper reveals that she was in fact the traitor because her father had been kidnapped. Jason and Leo resolve to rescue him, even though it jeopardizes the quest. Soon after, Lycaon and his wolves attack. Then, the Hunter of Artemis come in and save them. There, Jason discovers that the leader of the Hunters,Thalia, is his sister. Together they head up the mountain to meet Aeolus. Thalia turns back, and the trio face Aeolus alone.However, the master of the winds is angry that they aren't there to premote them, but Mellie, an Aurae blasts them to a cafe near Mount Diablo. On the mountain, they find Enceladus, the giant born to kill Athena. Jason faces off against Enceladus and manages to wound him several times. However because of his strength, Jason cannot kill him as it would take the power of a god and demigod. Jason's weapon breaks, releasing a massive amount of energy but fails to kill Enceladus. Jason calls on Jupiter to save him and his faith rewarded with an incredible lightning bolt, killing the giant. Hedge takes Piper's father home while the three continue on their journey.
From there, Leo flies Jason and Piper to the Wolf House, where Thalia and the Hunters of Artemis are defending against a pack of Lycanthropes and Earthborn. Because his sword was broken, Jason was forced to fight with nothing but a board. After Khione arrives and freezes all the Hunters, Jason watched as Leo fought her off. After Khione retreated, Porphyrion awakens and Jason decides to hold him off while Leo and Piper try and free Hera. Porphyrion wonders if Jason is Hermes or Ares, but laughs at Jason after learning he is just a demigod. Porphyrion allows Jason to boast, not feeling threatened at all. The two fight, with Jason clearly being outmatched by the still weak Porphyrion. Jason even manages to stab him in the ear and blast him with lightning, but it only served to blacken the giants face. It isn't until Hera is freed at Porphyrion retreats.
Hera unleashes her true form after warning the demigods to look away. Jason doesn't understand the warning and sees Hera's true form, which kills all the monsters still remaining in the area. Jason is put into a near death state, with Hera and Thalia both believing he is dead. Piper says he is breathing, something that Hera doesn't believe to be possible. Piper then uses her charmspeak to awaken Jason, much to the relief of everyone.
When he, Piper and Leo arrive back at camp, he is visited by Juno when he is in his cabin alone, and is given a new gladius as a replacement for the one he lost while fighting the giant, Enceladus. After this, a head counselor meeting was called, where he then revealed that he is from a Roman equivalent of Camp Half-Blood, and that is where Percy is most likely at. Jason also reveals that if the campers at the Camp Jupiter discover that Percy's from Camp-Half Blood, they may not be that nice. It is decided that he, Leo, Piper and Annabeth will go and find Percy at the Roman Camp and then set sail for Greece by sailing on the Argo II.
Jason is mentioned several times by the campers of Camp Jupiter, because they've been wondering where he has gone. Percy has a brief dream of Leo working on the Argo II with Piper and Jason behind him. As well, when Percy, Frank, and Hazel are watching Polybotes from afar Ma Gasket yells, "The camp, yes. Vengeance! The orange and purple ones destroy my home. Now Ma Gasket will destroy theirs," referencing how Jason destroyed her factory. After returning from their quest and saving Camp Jupiter, Leo sends a video scroll to ask for safe passage from the Romans. While Percy tries to tell them that they won't attack, he tells them that Jason is on board the ship, leading Reyna to allow the ship to land, but not without any kind of security.
At the beginning of the book,Jason is on the Argo II, along with Annabeth, Leo, Gleeson, and Piper, his girlfriend. He is seen wearing a Camp Half-Blood T-shirt with a purple toga over it, while holding a sword.
When the five arrive at New Rome, Reyna greets them and they hold a discussion outside of the camp. Jason introduces all of the members aboard except for Coach Hedge who is on the ship. During the discussion they discuss about who the seven are and Jason's adventure's at Camp Half-Blood. After the discussion, Jason asks Reyna if he could show Piper around New Rome. Reyna allows Jason to do so. When the Argo II starts firing, Annabeth spots Jason and Piper in the middle of a crowd of Romans who are throwing plates and stones at them. Frank however is able to save them after forming into a dragon and they escape onto the ship. Before they could escape Jason is knocked out from a stone thrown at his head.
Jason is unconscious, while the rest of the seven, save for Piper, look for items for the wrecked ship. Jason wakes up as Piper is telling the group they need head to mile marker Topeka 32. Piper explains that she saw a man with a silver goblet. Jason recognizes him as Bacchus and says that he did him a favor in wine country a few years back, accompanying Piper and Percy to meet him. The trio walks about a mile to the nearest mile marker and realize that Leo dropped them off further than they could walk. Percy and Jason have a contest to see who's companion can come the faster. Percy calls Blackjack who appears faster than Tempest, who Jason has only successfully called on three other times. With Piper riding with Jason, they head over to mile marker 32. When they are there they meet Bacchus who explains he planned on meeting Ceres. Throughout the encounter Bacchus calls Jason, "John Green." Suddenly Bacchus senses Gaea and flees.
Gaea has Eidolons enter Percy and Jason to fight. Gaea forces Piper to choose which boy she can save. Instead, Piper has Blackjack knock Percy out after she has knocked out Jason using her Charmspeak. They make it back to the ship where the boys are recuperating. Percy and Jason discuss whether or not they could have really killed each other until Annabeth breaks it up telling the boys, "I'm sure you both would be wonderful at killing each other" and that they need to hold a meeting. At the meeting, Piper tells the Eidolons who are still possessing Leo, Percy, and Jason to leave the ship. After the Eildolons are gone, Jason states that the Romans won't follow them past the Mediterranean Sea, as it is the place of no return and by crossing into it, they would all be listed as traitors of Rome.
Eventually, the seven make their way to Charleston and are under fire by the Romans who have caught up to them. Percy and Jason create a storm around the ship to push the Romans back and create a quick get away as the take off into the sky. They make it into the Pillars of Hercules and when they arrive they decide to send Jason and Piper to talk to him about passing through. Jason mentions that their quest was given to them by Hera, quickly angering the minor god, who sends them on the hard task of retrieving the horn of Achelous. The two demigods get the horn and go meet Hercules again, who gives them permission to pass as they had retrieved the horn. He then asks for the cornucopia, but Piper refuses to give it to him, as he doesn't deserve something as precious as the cornucopia. This angers Hercules and he prepares to kill them all, but Piper releases an unprecedented amount of food from the cornucopia, which completely buries the god. Jason then flies them to the ship and they start to take off.
After the ship has passed the Pillars, the ship is continually attacked. During this time Jason is defending the ship by throwing lightning and creating storms. This wears him out greatly. He switches taking watch with Percy whenever the ship goes into the water. Soon after the ship is attacked by Chrysaor, where Jason is quickly detained. They defeat him and fly into Rome safely. Once they are in Rome, Jason and Piper stay on the ship while the others scout out and have a picnic. Jason reveals that his birthday is July 1, which is the day they arrived in Rome. Percy comes back from dropping Annabeth off at her quest. Piper reveals her vision of a spiral staircase. The boys then persuade Piper to find these staircases.
When they find the staircase, Percy goes down first in case there is water, as he can breath in water and won't drown. When he comes back, he tells them he found something weird, which turns out to be a Nymphaeum. Soon, the nymph Hagno and several others, the nine nymphs that watched over Zeus when he was born appear and flood the chamber with evil water. Percy is unable to breath and the nymphs begin to drain the three of their power, stealing Percy's control over water, Jason's control over the rain, and Piper's beauty in order to be young again. Piper comes up with the idea to funnel all their positive thoughts into the Cornucopia, which releases the positive emotions as clean water. As the three release almost all their power into the Cornucopia, the nymphs become young again and spare the three, as the power they gave them as a gift and they restore the trio back to full strength, as well as telling them the location of Otis and Ephialtes.
They quickly arrive at their lair and find the jar Nico di Angelo is in unguarded. When they approach it, a platform lowers with one of the twin giants on it, Ephialtes. Otis soon joins his brother and they begin to talk about their plan to release monsters into Rome to destroy it as their biggest show yet. They had also planned on letting Nico die in public, but because of his death trance, he has been asleep and has no entertainment value, leading to the giants tipping over the jar and releasing him. Nico rolls out and Percy couldn't tell if he was alive or not. Percy tries to keep them distracted as Nico wakes up and begins to crawl away. The twins mention that even if Percy should be kept alive for the bounty, Annabeth is already doomed and Leo, Hazel, and Frank are locked up, meaning the giants can kill Percy, Jason, and Piper (they even claim to have choreographed their deaths). They also mention that Gaea will rise in only a month.
The three lunge into battle, with Jason attacking Otis, Percy attacking Ephialtes, and Piper trying to defend Nico from the released animals and monsters. A hydra is even released, leading Percy to set a large stack of fireworks off, which destroy the hydra, but also destroys many different areas of the twin's hypogeum and knocking out Piper. When Jason runs to her, Otis tosses his spear at him, which Jason deflects with a gust of wind and it strikes Ephialtes right in his side, turning him to dust. A piece of the ceiling also falls on Otis, turning him to dust as well. However, the two need to be killed by a god and demigod working together and they instantly reform. As they taunt Percy and Jason, Bacchus appears on the scene and raises them into the Colosseum, which Bacchus filled with ghostly spectators. However, Bacchus refuses tohelp unless the two can 'entertain' him. Jason and Percy agree to fight together this time and charge the two. Jason blasts the two with wind, causing the fake mountain the two were holding to fall on Ephialtes. After insulting Swan Lake, Otis charges the two and Jason blows him into the lake and the two stab him with their swords, turning him to dust.
Percy then uses the water to keep the dust from reforming, but Otis' head is able to reform. Ephialtes then escapes from the fake mountain and charges the two, managing to disarm them both and almost kills them, but the Argo II appears overhead and blasts them with Greek Fire from the cannons. Bacchus considers this entertaining enough and stabs both giants with his thyrsus, defeating them. Before leaving, Bacchus informs them of the best place to reach Annabeth before she is killed and vanishes. Leo, Hazel, and Frank rejoin Percy, explaining that Frank turned into a weasel and dug to the surface, where they managed to call Coach Hedge to rescue them.
Back on the ship, Jason watches as Percy and Nico argue about the two camps. Nico explains that Hades had shown him Camp Jupiter because he knew that both camps would need to work together. Nico also goes on to say he knows where the Doors of Death are on both sides, one in a temple in Greece called the House Of Hades, but the entrance in the Underworld is in Tartarus. Everyone agrees to worry about this later and head off to save Annabeth.
The Argo II arrives at the cavern where Annabeth is and blasts a hole in the ceiling. Jason, Frank, and Hazel all work together to help lift the Athena Parthenos onto the ship just as the floor collapses. As they are securing the statue onto the ship, Percy, along with Annabeth and Arachne, fall through the hole in the ground that leads to Tartarus. Afterwards, Jason feels guilty because he believes if he had flown down, he could have saved them. Nico tries to comfort him, by pointing out that even if Jason had flown down to get them, the only possible outcome would be all three of them falling down in Tartarus. They all decide to head for Greece to the Doors of Death, and hope that Percy and Annabeth are doing the same from Tartarus.
Jason has a dream in which he learns that Annabeth has managed to send a message intended for Reyna to Rachel Dare at Camp Half-Blood from Tartarus; Rachel, accompanied by Grover Underwood, delivers the message to Reyna, who is with Octavian and the other centurions of New Rome atop a Manhattan skyscraper. In order to stop the war between Camp Jupiter and Camp Half-Blood, Reyna must personally deliver the Athena Parthenos to Camp Half-Blood. Reyna then mounts her pegasus, Scipio, and heads for Europe, dismissing the protests of Octavian. Upon awakening, Jason directs Leo to change course for Split, Croatia, the site of the palace and tomb of the Roman Emperor Diocletian, a personal hero of Jason and Reyna, whose scepter is said to be able to control the spirits of dead Roman soldiers who worshiped the gods of Olympus.At Diocletian's tomb, Jason and Nico are confronted by Favonius, the Roman god of the west wind, and by Cupid, the Roman god of love, who are the guardians of Diocletian's scepter; Cupid extorts a confession from Nico as the price of giving him and Jason the scepter: Nico had fled Camp Half-Blood after Bianca's death not just because he felt rejected by the other campers as the son of Hades, and not just because Percy had let him down by failing to keep Bianca safe—he had romantic feelings for Percy, which he could not deal with. Seeing this, Jason tries to tell Nico that he would keep it a secret,but comments that everyone would still stand by Nico if he told them. However, Nico tells him that he's fine and no longer has feelings for Percy, though this is questioned later in the book.
Jason has also seen in a dream that Reyna is on her way, and, assuming correctly that she will take advantage of being in the region by visiting Diocletian's tomb, leaves a note for her near the tomb directing her on where to go from there.
As the Argo II continues on toward Greece, the weather becomes unseasonably and mysteriously cool and cloudy, and then Khione, the goddess of snow, who Jason, Piper and Leo confronted in The Lost Hero, attacks the ship and sends Leo to Ogygia, the island home of Calypso, in Malta, and in the process, freezing Jason in a block of ice.
Jason has had daily audiences with Auster, the Roman god of the south wind, in connection with the Seven being able to proceed on their way to Epirus. Auster is naturally capricious and indolent but yet seems increasingly disinclined to cooperate with Jason. Meanwhile, Jason has been thinking that he misses Camp Half-Blood and that he never really fit in at the more formal, traditional, even hidebound Camp Jupiter, and that he may have been changed irrevocably by his time at Camp Half-Blood. When Auster finally agrees to meet with him, he indicates that Jason is not committed to one course, Greek or Roman, personally; Jason's heart now lies with Camp Half-Blood, and Auster forces him to commit to it. Once Jason has done so, Auster changes to his Greek counterpart Notus and decides to send The Seven on their way. They then proceed to Valletta, Malta, where they find the Argo II fully repaired and moored out in the harbor so that they will be sure to notice it, and Leo at a cafe, pensive because of his encounter with Calypso; and they continue on to Epirus.
Arriving at the Necromanteion, Jason, Hazel, Frank, Leo, and Piper descend into the ruins, and eat barley cakes to protect themselves against the toxic potion they must drink in order to enter the temple, as per Triptolemus' instructions. Earthquakes strike the caverns as they walk through them, and monsters assail them. Nico uses the Scepter of Diocletian to summon ghostly Roman soldiers, but they will not obey Jason, as they sense that he is no longer Roman, and some, but not all, obey Frank, who may not command the entire force, as he is only a centurion. Jason stepped down as praetor and gives it to Frank, who then takes command of the undead soldiers and manages to defeat the monsters.
The five of them succeed in the quest to close the Doors of Death and rescuing Annabeth and Percy, and at the end of the book, Jason is seen talking to Frank in hushed tones, probably sharing old legends and stories of Camp Jupiter now that Frank is a praetor.
Jason is a very serious young man with a moderate sense of humor. He also has a strong sense of honor and justice as shown by his great compassion. He greatly cares for his friends and family willing to risk his life to protect or help them. Though a natural leader, Jason can be plagued by doubt and criticizes himself whenever he makes an error. There are notable similarities between Jason and Percy Jackson such as: their strong senses of justice and fairness, their loyalty to their friends, and the fact that they're both natural leaders. When on board the Argo II, Jason comments that he has never been surrounded by equals before, as most of the time people look up to him because he is a child of Jupiter. Jason is also very accepting of others, since, unlike many others, he felt no contempt or prejudice towards Nico, even after finding out that he was homosexual. Jason even offered Nico his friendship and support, and encourages him to take a risk and come out.
Jason is also very confident in his abilities. After he and Percy were possessed by the Eidolons and fought each other, Jason commented that he was worried that he could have killed Percy, instead of Percy possibly killing him. He also chooses to face Lityerses in combat instead of being turned to gold by Midas. Jason was even ready to face the Giant King Porphyrion, even though he knew he could not win.
|“||Never seen Jason fly before. He looks like a blonde Superman.||”|
Jason Grace is described as good-looking, having the features of a Roman statue, with electric blue eyes, tidy, military cropped blond hair which grew out during his time at Camp Half-blood, and a small scar on the corner of his lip from trying to eat a stapler when he was two years old. He says that he looks nothing like his father, which assumes that he looks more like his mother. He is very tall being one inch taller than Percy Jackson, with an athletic build, having muscular and tanned arms. His tattoo has the picture of an eagle with SPQR and twelve lines, indicating he has been at Camp Jupiter since he was three or four years old. Piper noted that his eyes seemed to hold some deep sadness, much like her father's. After his in counter with Sciron, Jason's hair has a grove in it where the robber shot him.
His looks attract female attention, such as the instances with Drew, and the girls from Wilderness School. Also, when Aphrodite gave Jason's team a makeover, Jason was the least modified, implying that Aphrodite approves of his physical attributes.
- ADHD: Like most demigods, he possesses inborn supernatural battle reflexes and senses that he uses to analyze the fighting style of his opponent.
- Combat Prowess: He is trained in Roman legionary warfare.
- Dyslexia: His brain is hardwired for Latin.
- Fighting skills: He is an expert spearman and swordsman. Jason's fighting skills are amazing seeing as how he bested Kronos' brother, Krios, a feat only Hercules has accomplished, who is technically Jason's older brother. He also slew the Trojan Sea Monster, easily defeated the skilled swordsman Lityerses, and dominated Mount Othrys by fighting through hordes of Scythian Dracanae and toppling Kronos' black throne. He has also shown to be able to hold his own against larger, more experienced, and more powerful opponents such as the Giant Enceladus and even defeat Titans such as Krios. When possessed by eidolons, Jason fought Percy Jackson on even footing (Piper couldn't believe the speed of their sword fighting), but later got injured. Jason can even use improvised weapons to fight as he used a wooden plank in the Wolf House to fend off numerous opponents.
Being the son of Jupiter, he is an extremely powerful demigod, that not only has authority over creatures of the sky but can also influence the forces of weather and can control the air around him. During his time at Camp Jupiter, Jason was considered the most powerful demigod in the legion. Hazel believes that Jason is the most powerful demigod she knows, however, the abilities of Nico and Percy seemed to have made her question her judgement, as she believes only Nico's power rivaled Jason.
- Aerokinesis: As a son of Jupiter, he can control and manipulate the air.
- He can control, and generate very powerful winds and air currents, powerful enough to instantly knock the giant Otis down.
- He can ride air currents, making him fly.
- He could see a path in the air, leading him to Boreas's palace
- He is able to dominate the will of more chaotic Venti.
- He can generate ropes of wind, "more tightly wound than any tornado" which he used to bind Notus' fiery Venti.
- Atmokinesis: As a son of Jupiter, he can control the weather.
- He can generate fierce storms.
- He can summon lightning bolts from the sky.
- Electrokinesis: As a son of Jupiter, he can control lightning and electricity.
- He is completely immune to electricity, having survived being struck by an electrical bolt "strong enough to kill twenty people."
- Like his sister, he can generate huge bolts and arcs of static electricity.
- He can send strong electrical shocks through others on contact.
- He can summon lightning bolts from the sky, though the effort drains him.
- Ivlivs: A coin made of Imperial Gold. It turns into a golden sword on heads and a golden javelin on tails when flipped. The weapon hasn't been named yet in the series, but the coin has the word 'Ivlivs' on it, which is Latin for 'Julius.' It was destroyed by Enceladus during his and Jason's fight on Mount Diablo.
- Gladius: Juno, the Roman form of Hera and Jason's patron, gives this to him at the end, so that he has a proper weapon. It is a Roman Gladius made of Imperial Gold.
Jupiter sired Jason, his second child with Ms. Grace. Like all the Roman gods, Jupiter rarely involves himself in the life of his child. Although it is unlikely that he has ever met his father, Jason is still given his aid when it is most needed.
Since Jason has forgotten most of his memories, we can imply that he wasn't taken care of by his mother, since Thalia said that she was the one who took care of him until Ms. Grace gave Jason away to Juno.
Jason's sister, Thalia Grace, was born to Zeus. Thalia is a Greek demigod, because when Zeus visited her mother the first time, he was in his Greek form. When Zeus came to Jason's mother for the second time, he came in his Roman form, Jupiter. Jason is therefore a Roman demigod, while his sister is Greek. It is shown that Jason cares for his sister. He feels somewhat depressed that Thalia has found a new family in the Hunters of Artemis. However, it is shown that when Jason first saw her picture, and Annabeth told him her last name, his instincts told him she is dangerous, as Juno left enough memory to know that digging up his past could be disastrous and that she was his sister.
She and Jason share many romantic moments throughout The Lost Hero. He has a great deal of concern for her, as he does everything to help her, such as when she says they should get together he says in his thoughts together, yes. He puts his hand on her waist to support her when she collapsed due to hypothermia. At the end of The Lost Hero the two have a romantic moment at the end of which they repeat what had apparently occurred in Piper's Mist induced memory of them kissing. Also, Jason has strong feelings for Piper, but he is worried for their future.
In The Demigod Diaries, Leo comments that Jason and Piper are dating, which takes place two months after their quest to save Hera. Piper also gives Jason a goodbye kiss just in case they don't get to see each other if the engine of the Argo II blows up. Since the engine did not blow up they continue to date for the next 6 months.
In The Mark of Athena, Annabeth introduces the two as boyfriend and girlfriend. She also gives him the nickname Lightning Boy. Piper constantly doubts that Jason does not have any feelings for Reyna, despite the many times he denies it. When the two are drowning (along with Percy), Piper mouths to Jason that she loves him.
The memory of her makes him rethink what he is doing with Piper,and makes him uneasy, though he does not know why. It's revealed in The Son of Neptune by Reyna to Percy that if Jason hadn't gone missing, a romantic relationship would have developed, since Reyna said that it was common for there to be romance between praetors, since they work together so much. When the Argo II arrives in the sky Reyna says that she hopes Percy is right and Jason is aboard the ship, stating that she has missed him.
In The Mark of Athena, it is stated by Jason, that he'd never felt more than friendship for Reyna. However, when the two once both went on a quest, after Reyna talked with Aphrodite, he states that she never acted the same to him again. Piper speculates that Reyna admired Jason mainly for his noble behavior and his good self-discipline.
Jason and Percy first meet in The Mark of Athena and have been shown to be on good terms. Percy says that Jason "thinks the same way he does" and mentioned a "spark of friendship." They both share many similarities: both are sons of one of the Big Three and extremely powerful demigods; both are excellent swordsmen; both are leaders at their respective camps; both hate Octavian; and both were chosen by Juno to be switched in order to bring the seven Heroes of Olympus together.Annabeth calls their relationship a "Budding Bromance", as the two seem to get along well. While fighting Otis and Ephialtes, the two are able to work well together as a team and manage to earn Bacchus' respect. It is also shown that when working together their powers get more intense when they created a huge storm at Fort Sumter, while fighting the Romans.
Jason and Percy also have a small rivalry going, such as when Jason and Percy both go for the head chair at a table and Jason even causes sparks to fly, but Annabeth took the chair in the end. Also, when apologizing to Percy after being possessed and force to fight each other, he comments that he could have killed Percy. Percy turns this around saying he could have done the same, but Jason doubts this unless there was an ocean in Kansas.
When Percy and Annabeth come out of Tartarus in The House of Hades, Jason is the first person to hug Percy in greeting.
Despite their time at the Wilderness School being fake, Leo still considers himself Jason's friend. He even volunteers to go on a quest with him and goes to repair the Bronze Dragon to give them a way of transportation. Despite Leo and Jason being good friends, Leo feels jealous of Jason. People look at Jason and respect him for being the son of Zeus (really Jupiter) and think he is handsome and powerful, while he only sees himself as the lowly mechanic. He also feels left out as Jason and Piper start to form a real relationship. The only time he doesn't feel jealous of Jason is when Thalia talks to Jason about his past and how Hera had taken him away from their mother. Leo remembers that while his own life wasn't that good, his mother wasn't possessive of Hephaestus and only wanted Leo to know him.
Jason starts to remember him at the end of The Lost Hero. When Juno returns some of Jason's memories, he remembers several of his friends, with Bobby being one of the names mentioned. Not much is known about him but his name. Bobby is only seen in The Son of Neptune when he gives Percy, Frank and Hazel a ride on Hannibal to the Camp Jupiter gates.The Son of Neptune, Hazel tells Percy that after she arrived, she had only known him for about a month before he disappeared, so they hadn't known each other well. Through Hazel's point of view, it is assumed that she and Jason were friends. She even compares Jason to Percy, stating that they both had the same look, as if they had both seen their fate, and were waiting for it to happen. When they both confront Sciron, in The House of Hades Hazel notes that couldn't figure Jason out well, as he acted "too perfect", and that she would rather have Nico, Frank or Percy at her back. Still, Hazel does trust Jason, and they cooperated well in defeating Sciron.
Because Jason kind of remembers her, it can be assumed they had been friends. In The Son of Neptune, she was a Centurion of the Fifth Cohort, but after the position was given to Frank, she retired after ten years of service to attend college in New Rome.The Lost Hero, Annabeth was the one who told him about Thalia, which sparked the memory of her and his last name, Grace. Annabeth claimed Thalia had never told her she had a little brother, but Jason insists that she does. At the end of the book during the Senior Counselors' meeting, when Jason tells where he's from and where Percy is, Annabeth says that she is going with them, mostly because of Percy. Jason agreed that he would want her along, mostly because he knew that she had already figured out where Percy was and the danger he could be in.
In the beginning of The Mark of Athena, it is shown that Annabeth distrusts Jason, thinking that he is too perfect because he always does everything nobly, does nothing against the rules, and even looks too perfect and she expects him to turn on them at the second they land. However, during their journey to Rome they come to rely and trust each other more, and after Percy and Annabeth fall into Tartarus, Jason feels responsible for not saving them.The Last Olympian), thus becoming uneasy about being around Nico. This, however, changes when they venture into Salona to retrieve Diocletian's Sceptre and encounter Cupid. Cupid forcibly makes Nico reveal about his true feelings for Percy, nearly reducing him to tears. Jason finally understands why Nico always shied away from people and was always alone and for Nico's sake, keeps it a secret. After the encounter, Jason becomes more empathetic towards Nico. At Notus' palace, Jason tries to befriend Nico as he feels it was the only way to help him out, but Nico once again pushes him away. Jason angrily retorts that Nico had run away from everyone for far too long and that he should come out of his shadows and trust Jason. Later, as they approach the House of Hades, Nico first offers the chalice full of poison to Jason, asking him to trust him. Nico fights along with the other demigods in the ensuing battle and it is implied that he and Jason are on good terms.
- Jason was named after the original Jason, a hero, by Jupiter to please Juno after being conceived.
- Similar to the original Jason, he was aided by Juno and was recognized by the fact that he was wearing only one shoe.
- Jason and Thalia are the only known siblings to be from different aspects of the same god. Thalia is a Greek demigod (being a daughter of Zeus), and Jason is Roman (being a son of Jupiter), as stated by Hera/Juno herself.
- Unlike other children of Zeus/Jupiter, Hera doesn't hate him or try to kill him like his other siblings. Hera said that she is Jason's patron and Jason is her champion.
- Thalia and Jason are both mentioned to like cheeseburgers, just like Percy does.
- The scar in Jason's mouth came from trying to eat a stapler when he was 2 years old. Because of this, Coach Hedge says he has 'excellent taste'.
- It is mentioned by Aeolus that Jason once stayed with him on a quest to kill a sea monster. It is later revealed Jason had killed the Trojan Sea Monster.
- Although one of the demigod "afflictions" is usually dyslexia, Jason could read Midas' brochure for Gold: Invest for Eternity just fine. Although it may have been in Latin or Jason may not have dyslexia, like Frank Zhang.
- Jason claims to be the Praetor of the First Legion in The Lost Hero, but Camp Jupiter is made up of only the Twelfth Legion.
- It is revealed in The House of Hades that he wanted the Twelfth Legion to be renamed as the First Legion.
- Jason sometimes feels uncomfortable with attention that is given to him due to him being the son of Jupiter and people expecting that that he will not fail.
- Piper calls Jason Sparky on occasion.
- Jason is the first mortal to see a god's true form and lived.
- Despite being Roman, Jason is a Greek name, meaning "healer". This is because Jupiter felt naming him after Juno's favorite hero would quell her anger.
- Jason's name being a way to placate Hera may be a nod towards his older half brother Heracles, who was named after her. Although it is to be noted that Hera did kill Heracles and his family.
- Jason's birthday is revealed to be July 1, the first day of the month named after Julius Caesar and was also considered Juno's sacred day.
- Jason and Piper are the only couple who aren't from the same camp (Jason's Roman, while Piper's Greek).
- In every book appearance he has appeared in except "The House of Hades", Jason has been controlled by another force and made to attack an ally:
- Jason's birthday is the first day of July. In November, The Greek form of his father, Zeus, closed all communications to and from Olympus. If you take every first letter of the months from July to November, it spells Jason (July, August, September, October, November).
- Like Percy, Jason is also named after a legendary Greek hero.
- Jason had wanted to rename the Legion the "First Legion", which symbolized a new start for Rome, but the idea was shot down.
- Jason's favorite treat from the New Rome bakeries is brownies.
- He is the only member of the Seven not to have met his Godly parent.
- He is the only one to have a sister with the same mortal parent, but different god aspect.
- When Jason, Percy, and Piper met Bacchus at the Topeka sign, Bacchus called Jason "John Green," which is the name of an author who also writes young adult novels.