Gwendolyn makes her first appearance. She appears to be close friends with Dakota and is allowed to vote in the Senate at Camp Jupiter. During the War Games, she is speared from behind, presumably by Octavian, and dies. Gwen returns from the dead almost immediately because Thanatos, the god of death, isn't guarding the Doors of Death. Later, Reyna decided to release her from service to Camp Jupiter (later replacing her with Frank) to reside in college and live a normal life. She is at the senate meeting when they are deciding on whether to let the Greeks land in their ship the Argo II.
Gwen is described as "optimistic" by Frank Zhang . She is probably what kept the Fifth Cohort more positive after all the hard times, them going from the best cohort in the legion, to the losers nobody wanted to be around. She is also a very encouraging and morale person.
- It was insinuatied heavily that Gwen was killed by Octavian during the War Games, a competition akin to the similar game of Capture the Flag at Camp Half-Blood. This fact was never truly confirmed, though the Fifth Cohort widely blamed Octavian. She came back to life, seeing that the Doors of Death were open in the Underworld.
- Gwen retired to go to college the day after the incident during the War Games.