A Phantom Monster is a type of Monster Card introduced by HelixReactor. They are initially stored in the Main Deck.
Phantom cards have grey-green border color. In a similar fashion to Link Monsters, they do not have a DEF stat, and instead have a stat named PRESENCE.
In a similar fashion to Pendulum Monsters, Phantom Monsters start out in the Deck, and then when destroyed, tributed, or used as Materials, they are sent face-up to the Extra Deck instead of the Graveyard.
Phantom Monsters in the hand can't be Normal Summoned/Set, and normally require to be first Phantom Summoned. Face-up Phantom Monsters in the Extra Deck can be Pendulum Summoned, as long as they have been properly Phantom Summoned first.
In a similar fashion to Link Monsters, as they do not have a DEF stat, Phantom Monsters cannot exist in Defense Position either. Their unique stat, PRESENCE, also plays a key role when Phantom Summoning them.
At the end of each turn, the PRESENCE of all Phantom Monsters on the field and face-up in the Extra Deck is reduced by 1. When a Phantom Monster's PRESENCE becomes 0, it is automatically shuffled back into the Main Deck. Changes affecting a Phantom Monster's PRESENCE are permanent, until returned to the Main Deck or hand.
Once per turn, during the Main Phases, each Phantom Monster on the field is capable of Spiritual Recharge. It means for the player to banish 1 Phantom Monster from their hand in order to increase the PRESENCE of another Phantom Monster they control by an amount equal to that banished monster's PRESENCE. Phantom Monsters cannot attack during the turn they are Spiritually Recharged.