This is about the anime character. For the monster itself, see Kato.
In the anime series, Kato is an old cat who is a legendary master of the martial arts. He prefers to live alone in the mountains, but after much pursuasion takes on two pupils, the Tainted Kat Brothers.
Unfortunately, the two young Tainted Kats give in to their darker natures and begin working for Naga, who sends them to kill the Searchers. Kato then trains Genki and Mocchi how to fight his wayward pupils.