1 Vegapunk (the genius) who predicted Seraphim to to be the most powerful beings in the history of the sea.

2 Hyped since the Dresrosa arc when Fujitora mentioned abolishment of walords.

3 Final arc villains along with Imu as they are his subordinates.

4 Kid seraphims survived Yonko attacks and S hawk cut a mountain and made Blackbeard sweat.Will grow up in the near future(Vegapunk mastered gigantification.