Teferi's Reproach

The following rulings focus on what it means if a player's life total can't change:

If an effect would set that player's life total to a certain number that's different than their current life total, that part of the effect won't do anything.

Choices made for permanents as they entered the battlefield are remembered when they phase in.

If a cost includes causing that player to gain life (like the alternative cost of an opponent's Invigorate does), that cost can't be paid.

Each Aura and Equipment that phases out attached to a permanent that's phasing out phases in with that permanent and is still attached to it.

The following rulings focus on the "protection from everything" keyword:

Spells and abilities that would normally cause that player to gain or lose life still resolve while their life total can't change, but the life-gain or life-loss part simply has no effect.

The following rulings focus on the phasing keyword:

A permanent phasing out causes a spell or ability on the stack to have an illegal target if it targets that permanent. As a spell or ability tries to resolve, if all its targets are illegal, that spell or ability doesn't resolve and none of its effects happen, including effects unrelated to the target. If at least one target is still legal, the spell or ability does as much as it can to the remaining legal targets, and its other effects still happen.

While a permanent is phased out, it's treated as though it doesn't exist. It can't be the target of spells or abilities, its static abilities have no effect on the game, its triggered abilities can't trigger, it can't attack or block, and so on.

If the target player's untap step is somehow skipped as their next turn begins, their phased-out permanents won't phase in until the next untap step they actually have, but they'll no longer have protection from everything and their life total can change again.

Effects that replace an event with having that player gain life (like Words of Worship's effect does) or having them lose life will apply and end up replacing the event with nothing.

Permanents that phase out with counters phase in with those counters.

Any one-shot effects that are waiting "until [this] leaves the battlefield," such as that of Banishing Light, won't happen when a permanent phases out.

If the target player gains control of another player's permanent and it phases out, if the duration of the control-change effect expires before it phases in, that permanent phases in under that other player's control as the target player's next untap step begins. If the target player leaves the game before their next untap step, it phases in as the next untap step begins after their turn would have begun.

Nothing other than the specified events are prevented or illegal. An effect that doesn't target a player with protection from everything could still cause them to discard cards, for example. Creatures can still attack a player while they have protection from everything, although combat damage that they would deal to that player will be prevented.

The affected player can't pay a cost that includes the payment of any amount of life other than 0 life.

Any continuous effects with a "for as long as" duration ignore phased-out objects. Any such effects will expire if their conditions are no longer met after ignoring the phased-out objects.

Gaining protection from everything causes a spell or ability on the stack to have an illegal target if it targets that player. As a spell or ability tries to resolve, if all its targets are illegal, that spell or ability doesn't resolve and none of its effects happen, including effects unrelated to the target. If at least one target is still legal, the spell or ability does as much as it can to the remaining legal targets, and its other effects still happen.

Effects that would replace having that player gain life with some other event won't be able to be applied because it's impossible for them to gain life. The same is true for effects that would replace having them lose life with some other event.

Each Aura and Equipment you control attached to a permanent that isn't phasing out phases in attached to that permanent if it can still be attached to that permanent. If not, it phases in unattached. An Aura that phases in unattached will be put into its owner's graveyard as a state-based action. The same is true with Auras attached to players.

If a player has protection from everything, it means three things: (1) All damage that would be dealt to that player is prevented. (2) Auras can't be attached to that player. (3) That player can't be the target of spells or abilities.

Protection from everything will usually prevent damage if it would be dealt to that player, but some damage can't be prevented. In this case, because their life total also can't change, that damage has any other effects that it may have aside from causing them to lose that much life (such as effects from lifelink or infect) and triggers and effects can see that damage was dealt even though their life total didn't change.

Phasing out doesn't cause any "leaves the battlefield" abilities to trigger. Similarly, phasing in won't cause any "enters" abilities to trigger.

Any creatures that phase in under their control as their next untap step begins will be able to attack and pay a cost of {T} during that turn.

If an effect would cause that player to exchange life totals with another player, the exchange won't happen. Neither player's life total changes.

If a token is phased out, it will phase in as its controller's next untap step begins.