Tapu Fini has a black torso and light blue hair. It has a white headband-like marking on its head and a white v on its chest. To the sides of this V mark are two violet shell-like extensions from which protrude two arms with three fingers, separated in a way that would befit webbed arms such as those seen in Golduck. It has a fin at the lower front and does not appear to have legs, but an oval shaped platform of sorts on which it stands. Its eyes have light blue eyeshadow-like marks and are light cyan with white eyebrows of sorts. Its shell is purple with a fin on top and a horn—when closed, this shell resembles a swordfish.
Tapu Fini is the guardian of Poni Island. It does not care much for humans, but is willing to help those who prove themselves worthy. It can create a thick fog that puts its opponents into a self-destructive trance; it uses this fog both to defend itself and as a test for people who seek its aid. It is able to create water that is said to purify anything it touches.