Xyz Material

Xyz Materials (pronounced ik-seez, エクシーズ素材, Ekushīzu sozai, known as Overlay Units in the anime), are the result of monsters being used in an Xyz Summon. When an Xyz Monster is Summoned, the monsters used in the Xyz Summon are stacked underneath the monster instead of being sent to the Graveyard (called "overlaid" in the anime), and so only one Monster Card Zone is occupied.

Xyz Materials are essential to Xyz Monsters as in most cases they are used for a card effect, such as that of "Number 17: Leviathan Dragon". Removing an Xyz Material for the effect of an Xyz Monster is referred to as "detaching". If the Xyz Monster is destroyed or banished from the field, any associated Xyz Materials are sent to the Graveyard. When an Xyz Material stacked under an Xyz Monster is removed or detached, it is sent to the Graveyard.

Xyz Materials underneath Xyz Monsters do not count as monsters, so if "Dimensional Fissure" is on the field, detached Xyz Materials will be sent to the Graveyard. Also they cannot be targeted or activate any of their effects.

Xyz Materials are not treated as being on the field, as seen in the October/November 2011 issue of Shonen Jump and later confirmed by Konami. When an Xyz Material is detached, any "leave the field" effects it may have are not activated, so for example, "Sangan" does not have its search effect activated upon being detached, and "Reborn Tengu" does not Summon a copy of itself when it is detached.

Prior to the ruling update and as an interim ruling, the rulings for Xyz Materials as "cards on the field" were different between the OCG and the TCG:
 * In the OCG, Xyz Materials are not treated as cards, and thus are not treated being cards on the field, so effects like "Sangan" do not activate, and "Plaguespreader Zombie" will be sent to the Graveyard when detached even when it was Summoned with its own effect.
 * In the TCG, Xyz Materials were treated as being on the field, so effects like "Sangan" and "Reborn Tengu" would activate when they were detached, and "Plaguespreader Zombie" would be banished when it was detached if it was Summoned with its own effect.

In Yu-Gi-Oh! ZEXAL, Xyz Materials are depicted as orbs of light colored the same as the Xyz Monster's Attribute, which orbit around their respective Xyz Monsters. Also, during an Xyz Summon, the Xyz Materials' corresponding Attributes light up their bodies. When the player detaches Xyz Materials for their respective Xyz Monster's effect, the Xyz Monster absorbs Xyz Material through several methods, such as, by their mouths, arsenals, etc. In some cases, the Xyz Monster will glow the color of the orb it absorbed before releasing its effect. This is also seen in Yu-Gi-Oh! 5D's Tag Force 6 when the player Xyz Summons a monster.