Wario

He first appeared in Super Mario Land 2 as the antagonist who stole Mario's castle. Then, Wario started appearing in his own series of games which include:

• Super Mario Land 3: Wario Land (Gameboy)
• Wario Land 2 (Gameboy)
• Wario Land 3 (Gameboy)
• Wario Land 4 (Gameboy Advance)
• Wario Ware Inc, Mega Microgame$ (Gameboy Advance)
• Wario World (GameCube)

Wario also appears as a secondary character in Mario games such as:

• Mario Kart 64
• Mario Golf
• Mario Tennis
• The Mario Party series

The name "Wario" can be taken to be a blending of Mario's own name with the Japanese adjective warui meaning "bad"; hence, a "bad Mario".