Ares is the bearer of the divine blessing of the Sage, the greatest of the mage blessings. When the party members caught up to Red's level, he kicked him out of the party for not being a "true" companion. He is a son of a failed duke and joined the Hero's party in order to restore his family's power.

Ares comes off as confident, compassionate and sophisticated, but he's far from it. He's revealed to be very selfish and cowardly as he is quick to give into fear when in battle and when he's constantly being compared to Red. After reuniting with Red and Lit, he becomes power-hungry and vindictive.

(Source: Banished from the Hero's Party Wiki)