- First of all, Deck Masters must be placed in the Extra Deck.
- Just like Pendulums, Deck Masters can have an additional Card Type (Effect, Fusion, Ritual, Synchro, Xyz, Link, Evolute...). However Deck Masters cannot be Pendulums (or Pandemoniums).
- At the start of the Duel, each player CAN activate ONLY 1 Deck Master from their ED (if they have one).
- Deck Masters are placed face-up in the center Spell/Trap Card Zone upon Activation, also, their owner has to pay a cost or follows some special rules (listed on the Deck Master) in order to be Activated.
- A player cannot Activate multiple Deck Masters with the same original name within the same Duel (however it is possible to Activate the same Deck Master multiple times in a Duel by using specific card effects).
- There can only be 1 face-up Deck Master card on each side of the field.