Afin

The partner to Ash within ARKS. He is not very enthusiastic about fighting on the front lines as a member of ARKS, yet continues to do so in order to "find" someone.

[Spoiler] Afin is looking for his older sister, Euclita, who vanished ten years ago when Darkers raided an ARKS ship. He realises that Euclita has become the new Dark Falz Apprentice, and vows to find a way to cure her.

In the next arc, he continues his crusade to bring his sister back. Through repeated encounters in the Mines and a little support from you and his friends, he finally gets through to Euclita and helps to purge enough of her Dark Falz power to return her to (relative) normality. [/Spoiler]

(Source: tvtropes)