A Mii is a personal digital avatar character that players can create and use in certain Nintendo games. Miis were introduced for the Wii alongside the system's launch late in 2006, and have since appeared for use on the Nintendo 3DS, Wii U, Nintendo Switch, and even certain Nintendo DS titles and mobile apps. Miis often make cameo appearances - playable or not - in Nintendo games and are sometimes the focal point, such as software like StreetPass Mii Plaza and the Tomodachi series, and gained representation in the lineup for Super Smash Bros. 4, and later Super Smash Bros. Ultimate, eight years after their original introduction.
Miis debuted along with the Wii in late 2006. They can be created using the Wii's Mii Channel application, with users able to customize many aspects of their appearance and facial features, such as their height, hair style and eye color. Once created, Miis act as avatars for players in a variety of titles, such as Wii Sports, and as a way of keeping track of individual players' scores. Miis saved onto a console are also capable of appearing as NPCs in games, usually acting as bystanders or spectators. While initially exclusive to the Wii, Miis would also see use in a few Nintendo DS games (the most notable example being the Japan only Tomodachi Collection), and later in several games on the Nintendo 3DS and Wii U, with the latter two being made using the Mii Maker application preinstalled on the system. Miis would return on the Nintendo Switch, but were made less of a focal point within games themselves - Super Smash Bros. Ultimate is one of the few to contain Miis within the game. Color choices were greatly expanded on, and Miis were available from day 1 as options for profile icons with a variety of facial expressions and poses.
While not playable, any Miis saved on the Wii console could be used as personal icons in the game's Friend Roster.
There exist multiple rumors on the inclusion of Miis in Brawl, with most claiming that Masahiro Sakurai did not want Miis in the game, saying "They have an innocent charm to them that could be ruined if they were in a fighting game." No website or print source, however, is known to corroborate these claims. This quote was, however, used when explaining why Villager or another Animal Crossing character wasn't added in Brawl.
During E3 2014, when introducing the Mii Fighters, Sakurai claimed that Miis were considered as potential playable characters in Brawl, but were ultimately not included because "it didn't seem right at the time for Miis to be punching and kicking".
As a playable fighter
Main article: Mii Fighter (SSB4)
Miis, under the name of Mii Fighters, are customizable fighters in Super Smash Bros. 4. They can be one of three types: the Gunner, which places emphasis on long-range attacks; the Brawler, with its close-range fighting style, fast movement and powerful physical strikes; and the Swordfighter, the weapons master. Each of the three types have access to twelve unique special moves, and can also be customized with different clothes and accessories. Despite not originating from it, Mii Fighters are counted as a part of the Super Smash Bros. universe.
On the fourth and current tier list, which does not take custom special moves into account, the Mii Fighters are unranked, though on the previous tier list, Mii Gunner, Mii Brawler, and Mii Swordfighter ranked 54th, 56th and 57th respectively. Mii Brawler possesses good mobility, attack power and speed, yet has a lackluster reach and poor recovery. Mii Gunner has generally quick attacks and high reach, especially with its forward smash and up aerial, yet has a terrible grab game due to a lack of damage and an inability to start combos, along with mediocre mobility and a lack of ranged KO options. Mii Swordfighter has a disjointed range, quick grab, and versatility in its various special moves, but suffers from a lag-filled moveset and difficulty in KOing. However, the biggest drawback the Mii Fighters have are the banning of custom moves in tournaments, which has been in effect since EVO 2015. Due to this, they are forced to use only their default movesets, rendering their current potential and overall viability poor. As a result, all three Mii Fighter types have some of the worst tournament representation out of the entire SSB4 roster.
Mii characters also appear in the background of several stages. In these cases, the Miis featured can either be those already on the console, or random Miis generated by the game.
In Multi-Man Smash
Main article: Fighting Mii Team
Additionally, Mii Fighters appear as enemies (under the name "Fighting Mii Team") in the game's Multi-Man Mode, as well as the retooled Classic Mode. Succeeding the Fighting Alloys from Brawl, members of the team are taken from Miis in the player's Mii Maker, though randomly generated Miis are also present in the mode. All Miis featured as Mii Fighters are randomly chosen to be Brawlers, Swordfighters, or Gunners, but they cannot use special moves or grab ledges.
Mii Fighters have a unique costume when fought as part of the Fighting Mii Team, consisting of a black shirt with a large, white M on it, as well as stylised trousers featuring some stripes shaped like the lowercase letter I. These Mii Fighters also do not change facial expression when attacking or attacked, as if the Mii faces are nothing more than masks.
In Smash Tour
Miis are used as the players' tokens in the boardgame-like mode, Smash Tour, simply being used to move around between spaces and collect pick-ups. They appear to wear the same outfits that they do in the Mii Maker as opposed to their standard Mii Fighter uniforms, though they will not wear their favorite colors, and instead wear either red, blue, green, or yellow depending on which player or CPU they represent. The Miis that are automatically loaded as representatives for CPUs are chosen at random, and the chances of a Guest Mii being chosen depends on how many Miis have been created on the console in question.
As a playable character
Main article: Mii Fighter (SSBU)
Miis return in Ultimate. Their proportions have been altered so that they have smaller heads and they now have 12 different voices to choose from. Each Mii Fighter can choose from one of three sets of special moves, some of which are new or altered. They are once again customizable characters, but are now the only ones with this distinction. Additionally, unlike the previous game, each Mii Fighter class is selected separately on the character select screen instead of sharing a slot, unless the character select screen is set to stacked mode.