#13 Final Fantasy VI: Psycho Cyan
I played the bajesus out of FFIII/VI but I never experienced this sociopathic behaviour. Apparently, when you revive Cyan during battle while he’s still in imp form, he turns into a crazed maniac and would not stop bludgeoning his random target until they turn into a fine, red mist. His brutal wrath wasn’t focused only on monsters; party members were susceptible as well.
I guess Cyan took his ‘my-family-is-deeeeeeaaaad-rage’ out on anyone and everything. Batman would be proud.