Jason is described as having blond hair, blue eyes, and a scar above his upper lip (said to be a result of an attempt to eat a stapler). He is of above-average height, with an athletic build and muscular arms. By the age of fifteen, he has earned the rank of praetor and leads the legion with his longtime partner, Reyna. Jason also coordinated the Roman camp's attack on the Titan force. He led an assault against Mount Tamalpais/Othrys, a Titan stronghold near San Francisco, and defeated the Titan Krios in combat, much as Percy Jackson defeated Hyperion and helped to defeat Kronos. Of all the characters in the series, Jason is the one who struggles the most with the differences between the Greek and Roman perspectives. Piper McLean describes Jason as very rule- and duty-oriented, though Terminus describes him as a rule-flouter. When the Argo II is stuck in North Africa, he must choose one identity or the other. He chooses to consider himself a Greek, despite his parentage, and is later unable to command a legion of Roman ghosts. During The House of Hades it is revealed that Jason has plans to return to Camp Jupiter to improve it with things he learned at Camp Half-Blood, such as giving the fauns (the Roman equivalent of a satyr) more rights and responsibilities. Later, during The Blood of Olympus, Jason decides to consider both the Greek and Roman traditions as part of his heritage. He becomes Pontifex Maximus, a role which will see him travel between Camp Half-Blood and Camp Jupiter to build shrines for every god and goddess in the pantheon.