Tremaine

In "Overpowered Villains (again)"
Tremaine is fighting Super Villain, when he is stabbed in the stomach. He is saved by his friend, but he is overpowered and Super Villain runs to kill him.

In "When the writer of a show only focuses on progressing the plot."
Pitfall is being confronted by (possibly) Tremaine. Tremaine is telling him about all of his powers. Pitfall attempts to attack Tremaine, but gets his hand cut off in the process. He regenerates his hand back, throwing off Tremaine's cool composure. Pitfall explains his regeneration ability and how he learned it right before the fight, breaking the 4th wall. Tremaine stabs Pitfall in the heart, but it is revealed that he never hit him in the first place. Pitfall walks away explaining his plan, while Tremaine rants about bad writing.