Catseye was the person in Hogfather who brought the group of five ‘businessmen’ who assist Mr. Teatime in his invasion of the Tooth Fairy's castle tegether. These businessmen were property and people removers (thieves and murderers), but are unlicensed by the guilds of Thieves or Assassins. They found plenty of employment from people who did not want to put the guilds to any trouble, frequently members of the guilds itself.
Catseye took his name from his reputation for being able to see in the dark, which turned out to be compensation for his deepest fear, the darkness of the cellar he used to be shut in as a child. When a security guard in the Tower of Teeth was brought to Teatime, he said to the man, “I am your worst nightmare.” Unfortunately for Catseye and three of the four businessmen, their worst nightmare was in fact the Tooth Fairy, who in the 'long before' was the original bogeymen, the gut wrenching terror in the dark and shadows. Catseye was the first to go, leaving his boots behind and a taste in the air of rats, damp and mold when his shadow claimed him.