Number C

"Number C", known as "Chaos Numbers" ( Kaosu Nanbāzu) in the OCG, is a sub-archetype to the "Number" archetype. They are used by Yuma Tsukumo, Reginald Kastle, Misael and Alit in the Yu-Gi-Oh! ZEXAL anime and Yu-Gi-Oh! D Team ZEXAL manga and are supported by "Rank-Up Magic - Barian's Force" and "Rank-Up Magic - Limited Barian's Force".

They are are upgraded versions of the base "Number", which are Summoned by overlaying their base counterpart through Chaos Xyz Evolution. So far, all "Chaos Numbers", if they are Summoned normally rather than by Chaos Xyz Evolution, require one more material than their normal versions and require the materials to be the same corresponding Attribute.

In the anime, the player must have 1000 or less Life Points to be Summoned while in the OCG/TCG, you must have the aforementioned amount of Life Points to activate their effects. When summoned with 1000 or less Life Points, they keep the same ATK and DEF. They are summoned by reverting to their sealed form and entering the overlay network. When summoned through Rank Up Magic- Barian's Force, they have a higher ATK than their previous forms. They are summoned by turning into their attribute color and entering the overlay network. They then exit a door with the Barian's Emblem being broken and their sealed form spinning in fire before its sealed form is shown.

When Number Holders have a high level of a certain emotion, Chaos Numbers start to appear. For example, Astral and Yuma obtained "Number C39: Utopia Ray" after Astral was happy to know Yuma considered him a friend. Reginald Kastle also obtained "Number C32: Shark Drake Veiss" after his desire for revenge, brought on by "Number 32: Shark Drake", overpowered him.