Bowser

Appearance
Bowser is a giant turtle-like monster called a Koopa with a green, spiked shell. He's yellow and has horns. He has a green head and red hair. Sounds crazy, right? Bowser is the evil king of all Koopas and his goal is to defeat the Mario Bros. and get Princess Peach, once and for all.

Personality
You don't want to meet this guy in a dark alley, or even a bright, sunny alley. He's pure evil and thinks he's all that and always fails to steal the princess and marry her. He always has his un-faithful sidekick, Steve Goomba, on his side.

Bowser Jr.
Bowser Jr., of course, is Bowser's son. He used to have many other kids called Koopalings, until the Mario Bros. wiped them out. Now, all he has left is Bowser Jr.

Steve Goomba
Steve is Bowser's little Goomba sidekick. You would think his sidekick would be Bowser Jr. Bowser usually never goes on a quest without Steve, unless he needs him to do some castle work.