New Mii Fighter costume sets are to be released as paid DLC next year according to Nintendo's official support site, priced at 75 cents each.

There are five new Mii costumes that fans can play as starting on June 30. Three of them are brawlers, while the other two fight with guns. The first costume shown was another character from ARMS ...

Geno was actually first released as a downloadable Mii character for Super Smash Bros. for the Wii U and 3Ds back in 2015, but many didn't consider that to be good enough.