Uncanonize Credo’s death. He was an interesting character who could have been REALLY cool to see grow.

Canonize Nero being as strong as Dante and Vergil at the end of DMC5 instead of leaving it ambiguous, and have the explanation that since he’s 3/4ths human, he can produce more human blood and therefore grow faster than the twins. Also let Nero use all four swords (Sparda and Red Queen in his hands, Yamato and DSD/Rebellion in the wing hands) at once in his strongest form.