Catherine: Full Body Collab is a Ragna BreakFORUM
As said in the title. This special season RB will come to KR and JP on Sep 29th, and is expected to hit Global very soon (I don't expect we'll have two RB back-to-back, but it's not entirely out of question). Katherine seems to be this Ragna's boss with special boss costume. Catherine and Rin haven't been revealed yet. Correction: Change the boss from Catherine to Katherine and the fact that Catherine hasn't been revealed.