The free-to-play online RPG is currently available across PC, PS Vita, and PlayStation 4 in Japan. It will celebrate its fifth anniversary in 2017. Various updates suited to the fifth anniversary are still to come, including the climax of the Episode 4 story, the new “Battle Arena” content, and more.
Sega is planning all sorts of in-game campaigns in commemoration of the downloads milestone. Details will be announced at a later date.