Cross

Cross is a major character of the series.

Early Life
Before calling himself Cross, his name among the Original Dozen was Ares. He was one of the twelve people of Earth who were the first to settle on Mars. After a disagreement with Volk on how to preserve Mars's resources, Ares left the dome cities, called himself Cross from then on, and lived out in the wilds. Cross came across Layla after the colony ship she and her parents were aboard was destroyed and took her in. He trained her to survive out in the open and in the art of gladiator battles. In that time, he told her that Volk was responsible for her family's demise.

Layla and Cross then went separate ways, Layla becoming gladiator representative of Serena City and Cross living out in the open.

Layla's Quest for Vengeance
During Layla and co.'s journey, Cross meets up with Layla once again after Jupiter's death. He tries to talk her out of her need for vengeance, going as far as to call himself Volk so she can kill him in hopes of satisfying her need and moving on.

Fate
Layla and Cross battle, resulting in Cross's death. Before he dies, he says, "Now Layla, find the true meaning of your journey."

Etymology
As a member of the Original Dozen, Cross took the name of one of the Greco-Roman gods, Ares. Ares is the Greek god of war whereas his Roman equivalent is Mars. After disagreeing with Volk, he crossed himself out of the Original Dozen as an act of self exile, hence the name.

Trivia
Cross can be compared to SSS, a character from another animated series by Bee Train called Madlax. Both Cross and SSS are mentors of the main protagonist of their respective series while showing concernment for their well-being.