Ka was originally supposed to be a coyote, but he has since become a generic canid of some kind.

"Ka is Victor's older brother by two years. Whereas Victor is an illegitimate son, Ka is a true son of their father and doesn't understand why Lord Tannim spends so much attention on Victor.
Ka was originally purest white with off white tips, but his jealousy and hatred drove him mad. So mad that he traded some of his divinity for demonic power. When he did his fur became off white with black tips, he grew horns, and he can no longer enter into the Celestial realms."
--A Brief History of the Realms of Trux, Volume 1, page 665

Ka also has issues with anyone taller than him... which is just about everyone since his transformation left him at only 3'9".

Ka is a malicious little asshole with the power to make Victor's life miserable.