Cait Sith is a Fairy that takes the form of a cat. Its name means "fairy cat." The Cait Sith can converse in human tongues and walk on two legs, making no sound as it moves. It normally lives as a cat that travels back and forth between the cat kingdom and the human world. It has a white star-shaped mark on its chest. The Cait Sith appears in Irish and Scottish legends and served as the model for Puss-in-Boots.
Cait Sith appear on Suginami field and within the bronze and silver levels of Suginami Tunnels. A larger field boss variant plays a role in one of the earlier acts. Cait Sith appears as an NPC during the Foreign Country in the Woods quests and in the lower levels of Second Home.
"A fae beast from the Scottish highlands. Their kingdoms are in tree hollows or abandoned houses. Dog-sized, with vivid green eyes. Some live with humans, as they understand our speech."
—Persona 5 Royal background
Caith Sith is the second Persona of the Magician Arcana and can be found in Kamoshida's Palace, along with the Aiyatsbus area of Mementos. As a Shadow, he has the title "Hunting Puss in Boots." When itemized through Electric Chair execution, Cait Sith yields the Agi Skill Card.
"A cat fairy of the highlands of Scotland, said to have their own kingdom inside hollow trees and deserted houses. They are about the size of dogs and covered in black fur, except for their white chests. Their green eyes shine with intelligence, and they can understand human speech. They normally live in the kingdom, but there are times when they live amongst people as normal black cats. They are relatively gentle fairies, but when a person torments a cat, the offending human is dragged off to Cait Sith's Kingdom."
Cait Sith appears as a demon under the ownership of Airi Ban. This animated version of Cait Sith seems to specialize in Force attacks, being able to send out powerful blasts of Zan from its sword at a rapid pace.
It was first summoned (alongside Jungo Torii's Neko Shogun) in a scuffle against a rebel mob in Nagoya's JPs headquarters, and proved itself to be powerful demon, thanks to how fast it eliminated the opposing demons. It was also used to fight Phecda, though its attacks seemed to have no effect on it, and was destroyed alongside other demons by Phecda's beams.
It was later used to fight off Megrez, but thanks to Megrez's special recovery powers, Cait Sith's attacks were easily shrugged off until Airi summoned Lorelei to replace it.