Succubus

It does not break in and it does not take anything that was not handed over. That is the whole design and it is why the countermeasures people reach for do not work - wards, locks, guards and blessed thresholds all assume something is trying to get in. It arrives invited, stays welcome, and leaves the household smaller by degrees over a season, with everybody involved able to explain exactly why each step made sense at the time.

The Invitation: 30 ft, save Wis Mind, fail save roll 2d10+5 psychic. The target does not merely say yes - it wants to, and afterwards it remembers the reasoning and still finds it sound, which is why nobody takes it back. Cooldown 2 rounds. Draw Down: necrotic, melee 5 ft, +6 to hit, 2d10+5, usable only against a creature that has invited it, and it does not work on anybody else.

Invitation Given: while any creature present has invited it, it cannot be banished, compelled to leave, or attacked by that creature. Whether the invitation was freely meant or planted by the save makes no difference to the effect - that is the point of it. Withdrawn: the invitation can be revoked, aloud, by the creature that gave it and by nobody else, which strips all of the above at once. It will not do so on its own, because it does not think it was wrong. Somebody else has to make the case, out loud, well enough to change that creature's mind, and the DN should require an actual argument. Reduced to 0 HP after that, it dies like anything else and is very surprised.