Not much was known about Cait Shelter around Fiore. The guild seemingly possessed a tribal theme, with its members wearing garments reminiscent of those used by ancient Native Americans, with the vast majority of their members sporting body paint. The clothes were made by Cait Shelter itself, as Wendy Marvell noted that fabric-working was one of the guild's specialties. A limited group of people who knew about the guild considered its members the descendants of the Nirvit, an ancient tribe responsible for the creation of the forbidden Lost Magic, Nirvana. It was also believed that the Nirvit had the ability to seal Nirvana.
Cait Shelter's supposed headquarters lied in the northern portion of Fiore, not too far from Worth Woodsea, with a mountain range being located to the north of it. The building itself stood in a small plain, with rocky formations visible behind it. The formations housed tall, wooden watchguards and several massive poles; a large, round tiled space in front of the structure had more buildings overlooking it, with the local community, according to Wendy Marvell, being part of the guild.
The building itself was a large pavilion, which, living up to the guild's name, took the form of a cat's head. Its central section sported two large rhomboidal windows, which resembled feline eyes, each possessing two sticks placed in a cross shape crossing it; topping the cloth door standing in the central lower part of the pavilion were two curved corners, each bearing a pair of capsized triangular flags hanging from it, with their inner edges ending in a dark circle; something which made the whole entrance look like a cat's muzzle with an open mouth and bared teeth. The rounded top part of the structure, separated from the rest by a row of large feathers hanging vertically, came with a pair of massive, triangular protrusions, which served as the cat's ears, with the guild's name being placed below them, in the middle. Flanking this main section were two smaller ones, elongating from its sides, which possessed dark parts topping their roofs. Sitting behind the right wing from the main pavilion's door were three high poles, each bearing a banner secured to its central upper part by ropes: the banner in the middle was adorned by Cait Shelter's symbol, the one to its right by the emblem of Fiore, and the one to the left by the insignia of the Magic Council. Sitting before the pavilion, at both sides of the main structure, was a pair of large, ornamental objects similar to short columns, which in the upper part bore a dark symbol reminiscent of a wind rose; these very upper parts had their edges curving outwards, generating three protruding semicircles which made them look like paws, thus granting the feline structure its forelegs.
Inside, the pavilion was shown to have a wooden floor, and its fabric walls were sustained by a wooden frame, consisting of several large beams. The furniture was exotic, with carpets and clothes bearing ornamental patterns. Objects representing cats were also shown to be present, just like some vegetable elements, such as vines adorning the supporting beams.
While acknowledged as such by the authorities and even by the Guild Master of Fairy Tail, Makarov Dreyar, Cait Shelter has never been a guild. Its supposed Master, Roubaul, was in fact the soul of the last surviving member of the Nirvit tribe, as well as the creator of the Nirvana weapon, four hundred years prior to the current storyline. Such gigantic structure, which should have protected the Nirvit from the dangers threatening the rest of the world, eventually caused their downfall, with the darkness it had absorbed settling on the peaceful tribe and causing its members to fight and kill each other in a fratricide conflict which cost all of them their lives, with Roubaul passing away from old age some time after. Roubaul, employing his immense Magical capabilities, resolved to continue living on as a spirit, in order to wait in solitude for someone powerful enough who might have accomplished what he couldn't: the destruction of Nirvana. One day, however, his hermitage received the visit of a blue-haired boy, bringing an unconscious girl named Wendy Marvell and asking Roubaul to take care of her. Taken aback by the boy's resolve, the old man accepted. When Wendy woke up, she asked Roubaul whether "Jellal" had brought her to a guild, and the spirit, unwilling to disappoint her, confirmed that they were indeed in a guild, proceeding to employ his powerful Magic to generate a large number of illusions, each possessing a personality of its own. This is how the fake Cait Shelter guild was born.
Despite never having been a real guild in the first place, Cait Shelter managed to be recognized as such, taking part in the quest to destroy the Dark Guild Oración Seis alongside the legal guilds Fairy Tail, Lamia Scale and Blue Pegasus (with the Straw Hat Pirates to fight alongside them as well). Making up the group were two remarkable members: Roubaul, the one acting as the Guild Master, was an extremely powerful Mage, having created the Magic Nirvana and possessing enough skill in the use of illusions to generate a large amount of members for the fictitious guild, all possessing physicality and personalities of their own, something which amazed even Jura Neekis, the Ace of Lamia Scale and one of the Ten Wizard Saints, who described it as frightful Magic. What's more, the latter feat was achieved after Roubaul had passed away, with him continuing to live on as a spirit with the use of his Magic. The "cause" behind the guild's "creation", Wendy Marvell, is a Sky Dragon Slayer in possession of strong healing Magic, which was believed to be long-lost.