You may be looking for an article on the devil.
Lucifer, a character in a thoroughly odd fic, is technically Murdoc Niccals of the band Gorillaz reincarnated as a housecat. Agent Deuce, who sporked the fic in question, took the cat home and renamed him after bringing the real Murdoc to Medical.
In appearance, Lucifer is a black cat with one black eye and one red eye. Character-wise he is highly arrogant, though it's unclear whether this is because he has Murdoc's personality or because he's a cat. He has only been in HQ briefly, but has already had bad experiences with Molly Rath.