Obito/23y is a little patethic merman who was mistaken as a guppie
Itachi/19y is a half siren merman, really popular, likes to collect positive karma points
Kakashi/21y is a bachelor (like itachi) everyone wants him, he climed the status quo cuz his dad is hated
Kisame/25y is a warrior merman, who is dumb in a way, but a real scary one
So Obito is a very hated merman, as his mother is the infanous, bringer of ungortunate events, Madara. Hashirama is the last years winner of the bachelor beauty paegent, and is obsessed with Madara since childhood. Izuna lives in the outer skirts as he is a siren, and kills warrior mermen for fun. Tobiramas fav hobby is defeating Izuna. Also he stole Obito and claimed himself as the real parent, cuz he needs a child but refuse to make one, cuz if izuna kills him he will be a deadbeat father.
Kakaobi, kisaita, tobiizu, hashimada