A Deck Master is a monster that represents the player in a Deck Master Duel. It appears exclusively in the Virtual World arc of the Yu-Gi-Oh! anime, in which it is used in all Duels that take place in Noah's Virtual World.
At the start of a Duel, each Duelist chooses a card from their Deck (either their Main Deck or Fusion Deck) to be their Deck Master. The player's Deck Master starts the Duel visible, but not on the field. Deck Masters provide a Deck Master ability, with that ability being based on the card chosen as the Deck Master.
A player can choose to Special Summon their Deck Master to their side of the field at any time, but if a player's Deck Master is destroyed, they lose the Duel. If a player's Deck Master leaving the field is used to Summon another monster (such as being used as a Fusion Material, Tributed by a card effect that Summons another monster, or allowing a card such as "A Deal with Dark Ruler" to meet its activation conditions), the replacement monster becomes the player's new Deck Master. If multiple players' Deck Masters are used to Summon a single monster this way, the Summoned monster becomes the Deck Master of all players whose Deck Masters were used for its Summon.
If Fusion Monster was Fusion Summoned by using a Deck Master as Fusion Material, the Summoned Fusion Monster (now a Deck Master itself) can attack that same turn. (Under Battle City Rules, which the Virtual World arc uses a variant of, Fusion Monsters normally cannot attack the turn they are Summoned.)
Deck Master abilities
- The Deck Master mechanic is similar to Magic: The Gathering's Commander format, where each player selects a single Commander that can be summoned like any other monster but resides in the unique "Command Zone".
- The Deck Master mechanic is referenced in Yu-Gi-Oh! Duel Links by Tristan Taylor's exclusive Skill, Deck Master Effect: Cyber Commander. Interestingly, "Cyber Commander" was not Tristan's Deck Master in the anime.