Unstoppable monsters?

[Diferald]

Hey guys, Im a newbie dm and I would like some advice on how to conclude my campaing. Was planning on summoning some op monster that my PCs have no way on defeating directly and are forced to look for an alternate way like some kind of ritual or something. Any ideas?

[Adjoint]

What is your party's level and composition?

[Diferald]

Adjoint wrote:

What is your party's level and composition?

we are pretty far from ending the campaing but was planning on getting them there by lvl 15

currently they have an assassin, a cleric, a sorcerer and a barbarian

[Rysky]

There's the Implacable Stalker template.

[Adjoint]

There are also ghosts.

Bestiary, p. 144 wrote:

Rejuvenation (Su): In most cases, it’s difficult to destroy a ghost through simple combat: the “destroyed” spirit restores itself in 2d4 days. Even the most powerful spells are usually only temporary solutions. The only way to permanently destroy a ghost is to determine the reason for its existence and set right whatever prevents it from resting in peace. The exact means varies with each spirit and may require a good deal of research, and should be created specifically for each different ghost by the GM.

As a GM, you can also give this ability to any creature (making up a story how it obtained it), creating a creature that is no harder to defeat than a normal one, but difficult to get rid off permanently.

You can also give a creature a regeneration that can only be stopped by some specific action. See for example the story of Anteus who couldn't be defeated as long as he was touching the ground.

[Dosgamer]

Be wary of forcing PCs to resort to out-of-character solutions in order to defeat the big bad (BBEG). Part of the fun of making it to high levels in a campaign is getting to use those powers and abilities. Nothing wrong with making PCs solve problems and look for clues on ways to defeat the villain (maybe they have to find the ancient weapons or relics that will allow them to bypass the impossible damage reduction or regeneration), but let them use their abilities to defeat the enemy. Good luck!

[VoodistMonk]

Good old Lich-trick...

You have the phylactery be part of the loot. A beautiful adamantine dagger or whatever, something a party member is likely to keep rather than sell or discard.

Then, a couple days later, they wake up with the Lich fully rejuvenated and in the room with them.

This continues until they figure out the dagger is his phylactery and destroy it.

Liches are no joke, especially with some class levels. And even more so when it keeps popping up in the middle of your camp as you sleep.

[Diferald]

thank you all, really helpful