Ka-Oni-Santsu is a Zanpakuto forged by Zev Raregroove and given to Makuta Ynot. When first shown, it had the basic sealed form of a Katana, and a released form of a Scimitar. Later, its advanced release was revealed to be a flaming Phoenix. After centuries of training, Ynot later learned that Ka-Oni-Santsu had 6 releases, and 6 advanced releases, each being related to an element.
Ka-Oni-Santsu was sent to Xeno on Bara Magna by unknown means. Xeno has since returned Ka-Oni-Santsu to Ynot.
Since then, Ynot has discovered a Seventh form, Shadow. He also, during his 50,000 year training session, discovered it's ultimate form, the Blade Wing Style, but could not utilize it seeing as he didn't have the Seventh blade, which he now does, and is fighting Blackout with.
Ka-Oni-Santsu has seven forms based off of their own element, each having a Weapon and a Spiritual Beast form.
|Weapon Form:||Scimitar||3 katana||Kubikiri Hocho||Gauntlet and Glaive||Chain Blades||Staff||Claymore|
|Spiritual Beast Form:||Phoenix||Hydra||Minotaur||Centaur||Satyr||Pegasus||Leviathan|