Ubisoft

 (formally Ubi Soft Entertainment Software) is a French video game company headquartered in,. Founded by Christian, Claude, Gérard, Michel, and Yves Guillemot, they have developed games from numerous franchises, including ', ', ', and '.

Ubisoft has developed and published several games for Nintendo consoles. This relationship between the companies eventually lead to the Mario + Rabbids series, a series of games crossing over Nintendo's Mario franchise with Ubisoft's.

Mario + Rabbids series
Ubisoft has published the Mario and Rabbids crossover game Mario + Rabbids Kingdom Battle outside Japan, and the game has been developed by its Milan and Paris studios. Within Japan, it is published by Nintendo. The game has been successful commercially, becoming one of the best-selling third-party games on the Nintendo Switch. This would then lead to a sequel called Mario + Rabbids Sparks of Hope, also developed and published by Ubisoft outside of Japan. Mario + Rabbids Sparks of Hope is compatible with Ubisoft's service, and the Ubisoft character Rayman is set to appear in downloadable content for that game.

Other games
Trophies of Rayman,, and Barbara from the Rayman series are present in Super Smash Bros. for Wii U, and costumes for the former two characters, based on Mario and Luigi respectively, can be obtained in the Wii U version of  and its Nintendo Switch port Rayman Legends Definitive Edition. Rayman, Rabbid Mario, Rabbid Peach, and Rabbid Kong appear in Super Smash Bros. Ultimate as spirits, while items for Miis are available in the forms of a piece of headgear based on a generic Rabbid, and both headgear and an outfit (the latter for Mii Swordfighters) based on the Assassin's Creed character.

The Wii version of  features an exclusive track named "Just Mario" with the artist credited as "Ubisoft meets Nintendo". The song is a rearrangement of the Super Mario Bros. overworld theme and its backing video depicts Mario interacting with various elements from the game. This track returned in the Nintendo Switch version of .