Despite the game’s popularity overseas, none of the fans expected this game to come out in English because Japan in itself was pretty much infamous for never releasing their games overseas. For the longest time, the game was only available to play on DMM, just like other similar games such as Kantai Collection (KanColle).
For those of you unfamiliar with this type of game, Touken Ranbu was developed by Nitro+ and DMM, released exclusively on DMM Japan.