Code Monsters (コードモンスター Kōdo Monsutā) is a type of Monster Card. The color of these monsters are black, but with a dark blue computer chip background pattern. These monsters are placed in the Outer Deck.
Like Impure and Crystal Monsters:
- They do not exist in the hand, Main Deck, or Extra Deck. Likewise, any card effects that would place them in those locations returns them to the Outer Deck.
- To be properly Summoned, as with Extra Deck monsters, Code Monsters must be Code Summoned first. If they leave the Outer Deck without being Code Summoned, they cannot be Special Summoned if they are banished or in the Graveyard.
- Code Monsters currently can only be Special Summoned to a Main Monster Zone. Code Summon is not an Extra Deck Summon, likewise, they currently cannot be Special Summoned in the Extra Monster Zone.
Code Monsters have a Code Number in place of a Level or Rank. A Code Monster's Code Number determines the the total number of Code Materials required to Code Summon it, and the number of Code Counters the monster gains upon Summon. Because they do not have Levels or Ranks, cards that affect Levels or Ranks do not affect them and they cannot be used as Tributes or material for Ritual, Synchro, Xyz, Impure, or Crystal Summons.
When a Code Monster is properly Code Summoned from the Outer Deck, they will gain Code Counters according to their Code Number. It is for this reason that a Code Monster can only exist on the field in face-up Attack or Defense Position.
These Code Counters can be used as costs to activate effects and can be replenished with card effects. Negating a Code Monster's effect does not remove Code Counters from it, and Code Monsters are the only cards that can have Code Counters. The number of Code Counters a Code Monster can have can exceed its Code Number with card effects.