Mark is a Greek demigod son of Ares.
Percy Jackson and the Olympians
The Demigod Files
The Stolen Chariot
When Clarisse mentions that her brothers are messing with her, Percy instantly thinks of Mark and Sherman Yang, her brothers from Camp Half-Blood. This means they are possibly the most troublesome out of her siblings.
Abilities

- ADHD: Like most 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.
Demigod Abilities
- Physically Enhanced: As a son he Ares, he is very strong and swift.
- Warfare: He may have some small degree of powers that Ares himself possesses.
- Telumkinesis: 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.
- Necromancy (limited): As son of Ares, he can summon the losing soldiers in any war.
Trivia
- The name Mark is derived from Mars, the Roman form of Mark's father, Ares.