During the Granblue Fantasy 4th Anniversary livestream, Cygames, announced two major crossover events.
First will be a crossovers with Detective Conan, the classic anime and manga series,starting in April. Then in June, there will be a crossover with Persona 5, including an appearance by Joker and Arsène.
Granblue Fantasy has done this multiple times before, and it is exciting every time it is done, This is one game that knows how to market itself!