From the Super Mario Wiki
Ads keep the MarioWiki independent and free :)
Intelligent Systems is a video game company and affiliate of Nintendo. They have created the Paper Mario series and have assisted in developing the WarioWare series, since WarioWare, Inc.: Mega Party Game$!
They are also the producers of the Fire Emblem series, which was mentioned in Paper Mario: The Thousand-Year Door. They have also assisted in developing the Super Smash Bros. games Super Smash Bros. Melee, Super Smash Bros. Brawl, and Super Smash Bros. for Nintendo 3DS / Wii U, and also helped Nintendo to debug their systems and develop the Nintendo 3DS Camera application into the handheld system. In the staff credits for Mario & Luigi: Paper Jam, the company appears as special thanks.
Mario games developed