From ARMS Institute, the ARMS Wiki
Fighters are the playable characters that compete in ARMS. ARMS launched with ten fighters. As Nintendo stated before the game launched, five fighters were released as free updates after ARMS was released, bringing the total to 15. The last fighter, Dr. Coyle, was released on 2017-12-21.
10 fighters were available upon the games' launch; these were Spring Man, Ribbon Girl, Ninjara, Master Mummy, Min Min, Mechanica, Twintelle, Byte & Barq, Kid Cobra and Helix.
Max Brass became the first playable fighter released after the game's launch in Version 2.0.0, making him the eleventh fighter.
The twelfth fighter, Lola Pop, was released on 2017-09-13 in Version 3.0.0.
The thirteenth fighter, Misango, was released on 2017-11-15 in Version 4.0.0.
Springtron was introduced as an encounter in Grand Prix on 2017-10-17 in Version 3.2.0 but was unplayable until the game was updated to Version 4.1.0 on 2017-11-30.
Dr. Coyle was released and introduced as the boss in Grand Prix levels 6 and up as part of Version 5.0.0 on 2017-12-21, bringing the roster to 15 fighters.
- Springtron is the only fighter to not receive three signature ARMS, as he shares the same ARMS as Spring Man, based on how many the player has unlocked. Therefore, unlocking ARMS for Spring Man also unlocks the same ARMS for Springtron and vice versa.