Kotatsu-neko (Kotatsu Cat) is a huge ghost of a cat that froze to death a long time ago after being kicked out by his abusive owners one cold winter. The spirit of the cat decided to go bad and vowed to haunt the people who refused him shelter.
Because he died from cold Kotatsuneko is attracted to warmth. His spirit also had a strong attachment to kotatsu because his owners would never let him near one. Kotatsu are toasty little covered tables with a heater underneath to warm your feet. Kotatsuneko was pleasantly surprised to discover the heat that kotatsu emitted.
He's a nice and quiet kitty, who just sits with his paws under the table drinking tea and snacking on taiyaki (fish shaped pancakes). He's surprisingly carefree for a vengeful spirit and seems intent on living the good life now that he's dead. He tends to mind his own business and doesn't bother anyone, unless they bother him first. Being vengeful ghost, he has incredible supernatural powers and therefore he's almost unstoppable when he becomes cross; Usually using his brute strength and mastery of sumo wrestling moves to push his weight around. This sumo-kitty weilds more power than any other in the show (second only to Oyuki).
Partly the character of Kotatsu-neko serves as an animal mascot for the show. He adds a humorous element by just sitting there in the background of scenes kind of like those dappya monsters that keep showing up. It wouldn't be a complete show without a goofy looking animal character would it?
Kotatsuneko keeps popping up in the strangest places. Almost as if he has decided to haunt the show itself. Most of the time he's seen hanging around with either Cherry, Ten or the principal of Tomobiki High School. All other times he just haunts Ataru's room (of course Ataru being a magnet for bad spirits).
Voice: Tomohiro Nishimura
Kotatsuneko actually has a voice actor, or should I say noise actor since (excluding one episode) Kotatsu doesn't really speak, he just makes subtle noises. Anyway his seiyuu is Tomohiro Nishimura.