Jax is the son of Sparta however because of an incident when he was a child he's not turned into a purple rabbit that doesn't change how absolutely deadly of a fighter he especially with that katana he can just kill you in an immediate instant if he feels like it 

(I'm going to be so honest I know fucking nothing about Devil May Cry all I know is a few characters and the absolute banger that is the Casey Edwards tracks but other than that nothing so excuse any logic gaps)