Rules glossary
108.3 The owner of a card in the game is the player who started the game with it in their deck. If a card is brought into the game from outside the game rather than starting in a player’s deck, its owner is the player who brought it into the game. If a card starts the game in the command zone, its owner is the player who put it into the command zone to start the game. Legal ownership of a card in the game is irrelevant to the game rules except for the rules for ante. (See rule 407.)
- 108.3a In a Planechase game using the single planar deck option, the planar controller is considered to be the owner of all cards in the planar deck. See rule 901.6. (refs: 901.6)
- 108.3b Some spells and abilities allow a player to take cards they own from outside the game and bring them into the game. (See rule 400.11b.) If a card outside that game is involved in a Magic game, its owner is determined as described in rule 108.3. If a card outside that game is in the sideboard of a Magic game (see rule 100.4), its owner is considered to be the player who started the game with it in their sideboard. In all other cases, the owner of a card outside the game is its legal owner. (refs: 400.11b, 108.3, 100.4)