Disciple of Caelus Nin

Any one-shot effects that are waiting “until [this] leaves the battlefield,” such as that of Banisher Priest, won’t happen when a permanent phases out.

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.

The last ability means that no permanents phase in under any player’s control as long as Disciple of Caelus Nin is on the battlefield. This includes permanents that phase out in ways other than the first ability, and even permanents that are phased out already when it enters the battlefield. Once it leaves the battlefield, each phased out permanent will phase in normally during its controller’s untap step, with one exception (see below).