The game (announced at Evo 2017) combines 4 fighting-game franchises — BlazBlue, Persona 4 Arena, Under Night In-Birth and RWBY.
RWBY (pronounced “Ruby”) had already been rumored for a fighting game announcement in the week leading up to Evo 2017, beginning with this tweet from Rooster Teeth.
The trailer appears to feature a 2 vs. 2 tag system allowing players to choose two characters from each franchise. But outside of that, we’re not quite sure how the fighting game system will work out and will have to wait for more details from Arc System Works.
The game will most likely launch in 2018.