First, thank you for checking out our game, it means a lot to us.
Long story short there is the idea of "
You must be registered to see the links
" (親告罪,
shinkokuzai). This means if copyright holder doesn't complain about it, it's not illegal.
It falls similarly to doujinshi, but to prevent the copyright holder from complaining we are doing a few things to prevent this.
#1 - We don't have One Piece in the title.
#2 - We state that this is a parody and to support the official release.
#3 - We will not be selling the game, it is free; the only monetary gain we have is purely on Patreon.
Though if there are people out there more knowledgeable about Japanese Law, feel free to chime in and correct me if I'm wrong.