* CompleteMonster: ''[[MarketBasedTitle The Final Fight]]'': [[MadScientist Dr. Troy]], seemingly the best friend of [[Characters/StreetFighterI Ken Masters]], is in truth a [[BigBadFriend monster to the core]]. Creating the substance known as Cyboplasm with Ken's aid, Troy backstabs Ken by [[FakingTheDead faking his death]] and stealing their creation while infecting Ken with it so he suffers pain before wiping his memories to cover his tracks. Afterwards, Troy would trek across multiple planets to infest them with Cyboplasm so he can take glee in the pain it inflicts as his [[PainfulTransformation victims mutate into mindless superbeings]], with him intending to use the substance to take over the entire galaxy and trying to [[WeCanRuleTogether convince Ken to join him or die]]. Even when Troy dies, the Cyboplasm infestation he caused on earth still evolves into a plague.
* MoralEventHorizon: Initially a friend to Ken Masters, Dr. Troy crosses it when he backstabs his friend and infects him with Cyboplasm to inflict him with pain before trying to use it to inflict pain onto an untold number of victims across the galaxy before the overdose turns them into mindless beasts.