I believe it's Tempen Ni Gru...
Extended ending: They show Vergil after he falls to hell, and he gets up panting, then they show Mundus & start playing the music from the orignal DMC's prologue (& the place you fight Phantom) & he says "It'll be fun to fight with the prince of darkness... If my father did it, should be able to do it to!" then he withdraws Yamato & charges Mundus
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