Stern Mentor

For a player to mill a number of cards, that player puts that many cards from the top of their library into their graveyard.

A player can’t mill a number of cards greater than the number of cards in their library. If given the choice to do so, they can’t choose to take that action. If instructed to do so, they mill as many as possible. Similarly, the player can’t pay a cost that includes milling a number of cards greater than the number of cards in their library.

An effect that refers to a milled card can find that card in the zone it moved to from the library, as long as that zone is a public zone.

If an ability checks information about a single milled card but more than one card was milled, that ability refers to each of the milled cards. If that ability asks for any information about the milled card, such as a characteristic or mana value, it gets multiple answers. If these answers are used to determine the value of a variable, the sum of the answers is used. If that ability performs any actions on “the” card, it performs that action on each milled card. If that ability performs any actions on “a” card, the controller of the ability chooses which card is affected.

Soulbond is a keyword that represents two triggered abilities. “Soulbond” means “When this creature enters, if you control both this creature and another creature and both are unpaired, you may pair this creature with another unpaired creature you control for as long as both remain creatures on the battlefield under your control” and “Whenever another creature you control enters, if you control both that creature and this one and both are unpaired, you may pair that creature with this creature for as long as both remain creatures on the battlefield under your control.”

A creature becomes “paired” with another as the result of a soulbond ability. Abilities may refer to a paired creature, the creature another creature is paired with, or whether a creature is paired. An “unpaired” creature is one that is not paired.

When the soulbond ability resolves, if either object that would be paired is no longer a creature, no longer on the battlefield, or no longer under the control of the player who controls the soulbond ability, neither object becomes paired.

A creature can be paired with only one other creature.

A paired creature becomes unpaired if any of the following occur: another player gains control of it or the creature it’s paired with; it or the creature it’s paired with stops being a creature; or it or the creature it’s paired with leaves the battlefield.