Complex sentence: While acting as Roxas's mentor in the first half of "358/2 Days", he befriends the new Nobody as well as the other new member, Xion, eventually learning that Xion is an imperfect replica of Sora created by Xemnas.
Split into simpler sentences: While acting as Roxas' mentor in the first half of "358/2 Days", he befriends the new Nobody as well as the other new member, Xion. Learning that Xion is an imperfect replica of Sora created by Xemnas.