Actually it never was. This is what devs wrote in steam: "Fallen Legion won't launch with Japanese voice acting, but we hope we can add Japanese voice acting later. This game was co-developed with Mintsphere from Indonesia and YYT Games in the US."
look this. default was japanese and I wondered what language they have and changed english, chinese... but japanese is gone..:/ I delete this game and re-downloaded but no japanese. https://gyazo.com/60a3c3c3ba05bc3daa6023e65f169b5f
"Fallen Legion won't launch with Japanese voice acting, but we hope we can add Japanese voice acting later.
This game was co-developed with Mintsphere from Indonesia and YYT Games in the US."
I delete this game and re-downloaded but no japanese.
https://gyazo.com/60a3c3c3ba05bc3daa6023e65f169b5f
idk why japanese language is gone...