The Challenger Deep - Encounter the Beluga whales

So my rl friend (A.K.A @707_kuroyuki) asked me to do a story of this crossover au or whatever is this...Where Katsu befriended with ocean man Jotaro (This take place where main protags in Stone ocean survives but we'll get to that part how they survived later)

So each time i'll try to draw certain scenes that'll explain the story because i lost my skill at writing stories.I won't post the art on twitter or instagram because i'm pretty sure that my followers don't like when i post stuffs like this.So i'll post my Aus in here and my personal facebook.

Btw 'The Challenger Deep' is the Au's name.