Board Thread:Questions and Answers/@comment-27836345-20160224235840/@comment-5398287-20160225001111

Has a male voice and seiyu in both major dubs of the anime, I'd say that's proof enough of his gender being male. There was a lot of confusion over Ggio's gender back in the day too due to his appearance, but Kubo rarely does androgynous/somewhat feminine designs and actually has them be female, if ever.