When Player A uses Charm to move Player B's unit from base into a battlefield with Player C's units, who is the attacker in the resulting Showdown?

Question

Accepted Answer

Player B (the controller/owner of the moved unit) is the Attacker and gains Focus.

When Charm moves Player B's unit into a battlefield containing Player C's units, that Move causes the battlefield to become Contested and the unit(s) that moved are the ones that applied the Contested status. The Attacker is the player whose unit(s) applied the Contested status, so Player B is the Attacker and gains Focus [446.1] [459.2.b.1] [345].

Player A casts Charm to Move a unit controlled by Player B from their base into a battlefield containing units controlled by Player C. The Move places Player B's unit into that battlefield. Because the Move causes the battlefield to now have units controlled by opposing players, the battlefield becomes Contested and a Showdown is opened as a result of that Move [446.1]. The game identifies who applied the Contested status: the unit(s) that moved are considered to have applied it, and the Attacker is the player whose unit(s) applied the Contested status (i.e., Player B) [459.2.b.1]. As the Showdown begins, the player who applied the Contested status (Player B) gains Focus and is treated as the Attacker for the Showdown [345].

If multiple players’ units moved into the battlefield simultaneously such that more than one player’s moved units together caused the battlefield to become Contested, the determination of which player ‘applied’ the Contested status could depend on the exact timing of those moves; in that uncommon simultaneous-move situation the core rule text provided here does not explicitly resolve priority between multiple movers and further context would be required [446.1]. If Player A also had a unit present or also moved a unit to that battlefield at the same time, then whether Player B or Player A (or both) are considered to have applied the Contested status would depend on the exact sequence of moves and presence; the ruling above assumes only Player B’s unit was the mover that created the Contested state [446.1] [459.2.b.1]. If a battlefield ability or another effect changes which player is considered to control or make choices for abilities at that battlefield, those rules about ability control would apply separately but do not change the identity of the player whose unit applied the Contested status for attacker designation under the provided rules [FAQ:unleashed#9].

A Showdown opening due to movement is governed by the rule that a Showdown is opened when a Move causes a Battlefield to become Contested while it has no Units present from any player other than those that just moved [446.1]. The rules identify the Attacker as the player whose unit(s) applied the Contested status to the Battlefield [459.2.b.1]. In this situation the unit that entered the battlefield is controlled by Player B, so that unit is what applied the Contested status. Even though Player A cast Charm to force the movement, control/ownership of the unit that moved determines who applied the Contested status. Therefore Player B is the Attacker and, as the player who applied the Contested status, gains Focus as the Showdown begins [345].