Mii Fighters were added to Super Smash Bros due to growing presence and fan requests

Mii Fighters — the recent addition to the Super Smash Bros. Wii U and 3DS rosters — were initially considered for Super Smash Bros. Brawl, and despite initial misgivings about using Miis to fight, the evolution of their overall use eventually made the idea possible, according to Smash Bros. creator Masahiro Sakurai in his Weekly Famitsu column.

Sakurai said that the initial view of Miis — light-hearted, whimsical caricatures of Nintendo's players — made it hard for him to accept the idea of them brawling. There were also concerns that, if Miis were used in Super Smash, they would be associated with any potential bullying.

"Incorporating Miis was explored in the previous game, Super Smash Bros. Brawl, but I thought it over for about a minute and immediately decided against it," Sakurai said.

But as Miis' role in the Nintendo universe expanded — they are the first thing people see when they boot up the Wii U menu and are now used as personal icons — Sakurai decided that their importance was too great to ignore the possibility of a Smash Bros. roster slot. However, Mii Fighters can't be used in online play because of Sakurai's aforementioned bullying concerns.

"We don't want the online play to become a copyright free-for-all and it's probably not as fun to play against someone using a character based on someone you may not know," Sakurai said.

Ultimately, the main reason for the addition of Mii Fighters is the countless requests Sakurai has gotten to add specific characters to the game. Many fervently fan-requested characters have not been added due to copyright issues and development costs. But by using the Mii features, players can create and add any character they wish.

Super Smash Bros. will launch for 3DS on Oct. 3 and for Wii U this holiday. For more details on how the game plays, check out our in-depth hands-on preview from E3.