Bowser is the heaviest, and the strongest character of Ultra Smash Bros. IV and the main antagonist of the Super Mario series. He makes his fourth appearance in this game since Melee. Bowser is confirmed two days later after Captain Toad and Nabbit trailer, alongside with Peach. Generally in Mario's universe, Bowser is the ruler of the Koopa Kingdom and tries many attempts to kidnap Peach. But Mario is always on the front his road to protect her.
Bowser's voice is the same as in SSB4. Bowser doesn't possess a voice actor. Instead of that, he receives dinosaur, monster-like sound effects.