Wario (ワリオ?) is a fictional character in Nintendo's Mario series. The character was designed as another antagonist to Mario (besides Bowser), and first appeared in the 1992 Game Boy title Super Mario Land 2: 6 Golden Coins as the main antagonist and final boss. He was portrayed as an exaggerated version of Mario and his name is a variant of Mario's name (as shown by the W in his name, which is an upside down M that portrays him as an upside down Mario). Wario was first designed by Hiroji Kiyotake, and is voiced by Charles Martinet, who also voices many other characters in the series.
Since his debut, creators have developed Wario into the protagonist and antihero of the Wario Land and WarioWare series, spanning both handheld and console markets, in addition to many appearances in spin-offs in the Mario series, as well as also appearing in Super Mario 64 DS and Yoshi's Island DS. He has also appeared in other media such as the Super Mario Adventures graphic novel.
Read more about Wario: Concept and Creation, Promotion and Reception