His oath required no service beyond death, but his honor demanded it.

White Orchid Phantom

Flying, first strike
When this creature enters, destroy up to one target nonbasic land. Its controller may search their library for a basic land card, put it onto the battlefield tapped, then shuffle.

Modern Horizons 3

Flying, first strike
When White Orchid Phantom enters the battlefield, destroy up to one target nonbasic land. Its controller may search their library for a basic land card, put it onto the battlefield tapped, then shuffle.

Modern Horizons 3 Promos

If the target land is an illegal target when White Orchid Phantom's last ability tries to resolve, it won't resolve and none of its effects will happen. That land's controller won't get to search for a basic land card.

If the target land isn't destroyed by White Orchid Phantom's last ability (perhaps because the land has indestructible), its controller still gets to search for a basic land card.