The squid sisters (even though they're cousins)
The one on the left is Callie
The one on the right is Marie
One person guessed protagonists and they are right even though Callie was on Octavio's side in Splatoon 2 but that doesn't count because she was hypnotized another person guessed inklings which they are kinda right but there is a theory that they're cuttlefish
(cuttle-lings?)