ShadeStrider

In my opinion, Heihachi and Raiden are the only Playstation All-Star Battle Royale characters who have any business in Super Smash Bros Ultimate.

Heihachi was actually briefly considered by Masahiro Sakurai himself, but was passed over in favor of Pac-Man as a representative of Bandai Namco.

And Raiden is the adoptive nephew, protege, and number one fanboy of Solid Snake, a character already in Smash Bros Ultimate.