Super Smash Bros. for Nintendo 3DS and Wii U

Super Smash Bros. for Nintendo 3DS and Wii U are 2.5D fighting games for their titular systems, commonly referred to as Super Smash Bros. 4. They were released in 2014. This game introduces the three types of Mii Fighters: Mii Brawler, Mii Swordfighter, and Mii Gunner. Additionally, Mii-related games have seen a large increase in representation compared to in Brawl, including stages from StreetPass Mii Plaza, Tomodachi Life, and Wii Sports Resort, and the Wii Fit series receiving its own fighter, the Wii Fit Trainer.

Trivia

 * Much of the headgear wearable by Mii Fighters is taken from StreetPass Mii Plaza. These include generic items such as the Cat Ears and Devil Horns, hats from games within the software such as the Master Gardener's Crown and Mii Force Helmet, and hats based on other Nintendo franchises, such as the Barbara the Bat Wig or Fox Hat. Some of the latter, such as the Fox Hat, would be part of full costumes of their characters, but most in the former two categories would not return in Super Smash Bros. Ultimate.
 * Most of the downloadable Mii Fighter costumes based on existing characters were promoted with official Miis of the characters in question. QR Codes for these Miis were released on the games' official website.