The Twelve Kizuki are divided into two groups: six Upper Ranks, and the six Lower Ranks. The number signifies their ranking among the Twelve Kizuki, determined by each member's level of strength, Upper Rank One being the strongest, and Lower Rank Six being the weakest. The Lower Ranks have their numbers, and ranks engraved only into one eye, the Upper Ranks have their numbers in one eye and the kanji for "Upper Rank" in the other eye.