Sunder is a mutant and a member of the Morlocks. He was a close friend and ally of Callisto, the deposed leader of the Morlocks.
After the Marauders' massacre of the Morlocks, Sunder emerged as one of the few survivors. Some time afterwards, he relocated to Muir Island, appearing enjoying his time with Danny (Legion) and some Warpies children. During the Reavers' attack on the island, Sunder was shot by Pretty Boy and died. -Marvel Fandom
