>>590990According to his official bio:
"His artwork and Eiichiro Oda are greatly similar, but that is due to both of them being influenced largely by Akira Toriyama's work growing up. Eiichiro Oda and Hiro Mashima are both members of a generation who grew up obsessed with Toriyama and all things Dragon Ball , and whose styles were forged by Toriyama worship."
But he's apparently known as one of the "Kings of Plagiarism" in fan circles in Japan. So, it's no accident at all that Fairy Tail looks like One Piece. His previous manga, Groove Adventure Rave, was pretty mediocre and oddly, didn't look nearly as One Piece-like.