Azathoth, the Blind Idiot Rat, is just that. Blind and not particularly smart. But he gets by on feeling things with his tail and sheer ferocity. Though he can't always tell just who it is he's clawing, leading to many accidents involving him and the other Arkham escapees.

Shub-Niggurath, The Black Rat of The Forest With A Thousand Spawn, has a bad case of nymphomania and megalomania. She believes her numerous rat spawns will some day unite with her to take over the world. Blood Bowl is just a way to reunite her lost children.

Yog-Sothoth, The Key and the Rat, is a horrific kleptomaniac. He keeps stealing everything, and is the one responsible for getting the keys that let the Chittering Madness team out of Arkham Sanitarium. He's only in the Blood Bowl team because he has no direction in life.

Nyaralathotep,The Masked Rat, the Crawling Rat, the Rat of Many Masks, has a bit of an obsession with masks. He's killed a few people to take their skins to fashion beautiful masks or just to steal the porcelain masks on display. Now that he's out of Arkham he's promised to stop slaughtering people for their faces, and now works as the team's passer and messenger service to 'redeem himself'.

And steal more faces.

The King in Yellow, the Rat Who Shall Not Be Named, has a bit of a paranoia issue. He believes that if anyone were to see his face or say his name he will be forced to serve under them for a time or lose all his power. Thus, he covers himself in yellow robes and Blood Bowl gear and has told no one, not even the Blood Bowl organizers, his real name.

The recent addition of his second head has forced an update to his costume, consisting of an extra hood and an jury-rigged muzzle composed of some bandages. Not that that has stopped the second head from making a ton of noise.

Dread Cthulhu, The Great Old Rat of Madness, suffers from a unique form of Cotard's Syndrom in that he doesn't simply believe he's dead, but that his death is simply a sleeping of sorts for the day he may wake up and destroy the world. This sense of godlike immortality led to the crimes that got him into Arkham Sanitarium, and to help lead to the escape (Along side The King in Yellow) out of Arkham. He now allies with his Blood Bowl team, promising them that when he wakes up he'll put them beside himself as gods.

Yig, the Father-Rat of Serpents, wasn't initially insane. Quite the opposite, Yig was a very mundane Skaven. But his association with Bokrug got him thrown into Arkham Sanitarium. His time spent in that lock up lead him to believe he had given rise to all snakes and snake-like people. He collected a small following of Lizardmen, whom he used to help his 'fellow gods' break out of Arkham Sanitarium. He now uses Blood Bowl as a way to unify the lizardmen and snake people under his cult.

Ithaqua, the Rat-Walker, seems absolutely unaffected by the cold. This is actually due to a unique disorder in his brain's handling of his internal temperature that makes him ignore the cold. Mixed with some unintentional necromantic magic, Ithaqua is completely immune to the arctic temperatures of his homeland. This has lead him to believe his the most recent incarnation of some old ancient ice god named Ithaqua (He's not a god of creativty), and thus all others should bow down and respect him. Blood Bowl is his path to assert the Chittering Madness team, himself included, as a new pantheon.

Ghroth, the Harbinger, is a rat renowned for his singing voice. When the Dunwich Horror was forced into an early retirement Ghroth stepped up, and out of Arkham, to join the team. He is now usually the first person on the field, announced the team's arrival in a beautiful tenor and making sure the team doesn't oversleep. He's also responsible for a number of musicals, all of which tend to star him and tend to drag on for quite a while. Long enough that the audience tends to not care when the people sitting beside them start to disappear.

Father Dagon the Second, the Great Old Rat of the Deep, was actually a fan in Arkham Sanitarium who believed he had been possessed by the original Father Dagon upon Dagon's death on the field. Fans broke the second Dagon out of the Sanitarium and brought him to Mother Hydra. She deemed him to indeed be the new vessel for Dagon, took him as her husband, and brought him onto the team after her injuries forced her to step back and act as an assistant coach.

Bokrug, The Great Water Rat, was once a fisherman and close friend of Yig. But his tendency towards showing the fishes his 'godly grace' lead the both of them to be locked up inside Arkham Sanitarium. Now his madness has grown even grander, leading him to believe he is a god of fish and the water, and that all things must see his 'godly grace'. Whatever that might be at the time.

Tsathoggua, the Rat of N'kai, has an issue with weight management. Well, that and the delusion that food gives him power. His eating habits have likened him to a toad, thus leading him to believe that eating will cause him to morph into a toad god. The bat part's just for kicks.

Ghatanothoa, the Rat of the Volcano, is an incredibly ugly rat. He's the only rat on the team with scaly skin and a leg that seems perpetually broken. Ghatanothoa is also fiery and quick to anger. Ghatanothoa was jailed in Arkham Sanitarium due to his long long long history of starting fights and riots. Ghatanothoa believes that this violence somehow contributes to the collective chaos of the universe, thereby empowering the ones whom try to harness the entropy.

He claims to know how to do that, and in doing so he has made himself a god, but no one's really sure if he's lying or telling the truth. The Chittering Madness team believes him to some extent, and thus broke him out of Arkham Sanitarium to bring greater power to their team.