He has the same coloring a Koga ninja dog but instead his face is mostly white with black around his ears, eyes and part of his muzzle with. He has a slashed right eye and it is unknown how he got it.
He is known to be evil, impatient, rebellious, and persistent.
Izuna is an evil dog and the son of the Koga leader, Ryoga. Izuna attacks Kuma, an Iga dog, relentlessly and commands a small group of Koga dogs. He is young and rebellious but a skilled fighter, using his sword effectively.
He kills Hakutaka's brother, Toki and also kills Kuma but before he can kill Hakutaka, he is struck in the back of the head by an arrow launched by Ryojun. Izuna and his father retreat back to the Koga base and are seen to by their leader. Izuna isn't badly injured by the arrow and swears revenge on Hakutaka.
Izuna leads a small group of Koga Ganin to fight the Iga clan once again, this time he and his dogs kill Hakutaka's remaining brothers and father (although Ryoga was killed in the process).
Time passed after the death of his father and Izuna would still not give up, he challenged the Iga clan again but was ignored. He is not seen again.