Morph

Morph was a member of the X-Men. He was seemingly killed by Sentinels during the team's raid on the Mutant Control Agency headquarters. He later returned as a vengeful agent of Mister Sinister, angry with the X-Men for leaving him behind, though he fought his dark side and eventually helped his former teammates.

Morph eventually was sent to Muir Island for treatment. When he returned to the X-Men his first mission with them involved the Sentinels once more. Morph was filled with fear of having to face the beings that once tried to kill him.

However Morph eventually overcame his fear and even managed to destroy Master Mold. He once again left the X-Men after this mission feeling that he wasn't ready to be a hero yet.