|Son of Ares|
|Appearances|| The Stolen Chariot|
The Last Olympian
When Clarisse mentions that her brothers are messing with her, Percy instantly thinks of Mark and Sherman, which possibly means they are the most troublesome of her siblings.
Mark may have been one of the Ares campers that was convinced by a disguised Silena Beauregard to join the rest of the Campers in New York City in the battle against Kronos and his monsters. Only later did they realized that it was Silena and not Clarisse.
- ADHD: Like all demigods, he possesses inborn supernatural battle reflexes and senses that he uses to analyze the fighting style of his opponent.
- Fighting Skills: He is quite skilled with weapons.
- Dyslexia: His brain is hard-wired for reading Ancient Greek instead of modern languages.
- Physically Enhanced: He is very strong and swift.
- Warfare: He may have some small degree of powers that Ares himself possesses.
- Weapon Expert: Being a child of Ares would make him an expert in all weapon usage and may even have some degree of magical control over them.