Wario

Wario is the leading protagonist of the Wario series who was introduced as an antagonist in the Mario series. He is an obese, short and greedy man who sometimes helps Mario and his friends but on other occasions causes trouble with his mysterious friend Waluigi. He also manages a company in Diamond City called WarioWare, Inc.

Yoshi's Island DS
As an infant, Wario was involved in an adventure on Yoshi's Island to save baby Luigi from Kamek and Bowser while riding Yoshis.

Super Mario Land 2: 6 Golden Coins
Wario takes over Mario Land while Mario was in Sarasaland busy saving Daisy from Tatanga. After Mario obtains the six golden coins scattered across Mario Land, they both battle each other on the top of his castle and Wario is defeated.