Arena

Arena is a multiplayer mode in ARMS that supports up to 4 players. It pairs players into 1 vs. 1 battles, with up to two players being allowed to spectate. Arena is only playable in LAN mode, in a friend lobby, or locally. Arena was first shown during the ARMS Open Invitational and released alongside Version 1.1.0.

All battles are standardized to best-of-three fights with a 99-second timer. Items are also set to off. The only customizable rule is what stages are allowed to be randomly selected, with each one able to be toggled on or off.

Spectating
When two players begin a fight, any others will be forced into a spectator mode and can only watch the ongoing battle. While spectating, players can switch their camera angle at any time. Options include mirrors of either active player's view, a split-screen view similar to that seen in one-console multiplayer, or a dynamically-shifting camera.