Rin's daemon, named Kagami, is still in flux, but has the (eventual) settled form of a steel-blue whydah with brilliant blue eyes. Despite being female, she'll have the male plumage shown in that picture because aesthetic and no actual reason. Like cuckoos, whydahs are brood parasites that lay their eggs in other birds' nests. LIKE SATAN LAID HIS EGG IN A LADY. I guess.

Other forms she might take include an ocelot (his whole family is CATS), a rainbow boa (satan, snakes, you know. They're a thing), or a dark-colored kiko goat doe (SATAN!!!).

However, no matter what animal form she takes, Kagami is cheerful and talkative, but not too smart.