All of the carapacians, but especially the beta kids' Jack Noir/Bec Noir. All of the carapacians got SO shafted once Act 6 hit.

Bec Noir in particular was such a HUGE part of the beta kids' session, and was a literal amalgamation of things that were important to or representative of each of the kids. The fact that such a personal, intentionally constructed villain got essentially two scenes before being beaten in Collide was just a crime imo.