Obviously if you want to avoid spoilers, refrain from reading this before today’s Nintendo Direct (3 PM Pacific / 6 Eastern) ARMS Presentation.
Three unannounced ARMS characters have been leaked ahead of today’s Nintendo Direct, with trailers to go alongside them.
White Mask = Kid Cobra
New White-Haired Girl = Twintelle
Blue Robot Dude = Byte & Barq
You can check out the 4v4 character footage down below. The original video has been pulled since, but has been re-uploaded.