Imprisoning doorway

Imprisoning doorways were magical passageways that would bind any living things into it, as per the spell trap the soul. Those that had spell or magic resistance were in no way resistant or immune to these effects.

Anyone observing this nearby would simply see the creature disappear, as if it were entering a portal.

Release
These types of dread doorways could only imprison a certain number of creatures. If the door went above its threshold, those that had been imprisoned the longest would be released. Id any doorways were destroyed, they would release all the creatures it had taken in this manner.