Demi-Planes, Portals, Locks oh my...

[paul1612]

My google-fu is lacking.

I need a way using the RAW to create a doorway with a complicated clockwork lock & trap(s) that would protect a portal to a Demi-Plane (Library). That can't be simply defeated with a Knock spell(s), other magical roadblock erasers, and/or physical destruction/removal of the door. Basically I want the PCs to gather parts of the lock & keys to open a portal to a library of lost knowledge.

My only thought is ruling that the door isn't technically locked without the missing parts but as the Knock spell says "trick boxes" and "loosen welds" I'm not sure that works.

They are mid level so planar gates/transport isn't an issue though proofing the demiplane Library would be nice too if folks have some thoughts.

I realize Rule 0 is an option but I'd like this to be RAW.

Thanks for you time.

[The Mighty Chocobo]

A ring of Maximized Disintegrate traps around the door to destroy it with Minor Artifact level locks that can't be knocked or disable deviced keeping them active and undefeatable.

[Shin Bilirubin]

Permanent Spellbane? It's works as an antimagic field, but only against a specific selection of spells, I.E. Knock

[paul1612]

Thanks Shin - Well it's not listed under the Permanency spell list but it seems like 'GM may allow...' gives me carte blanche - I find it odd that any lock anywhere can be defeated by a 3rd level caster...Maybe a new spell: Lesser Spellbane (5th level pick one spell otherwise like Spellbane) makes sense.

[Claxon]

Make you're entire permanent demi-plane a dead magic zone. Have the door be slightly insidethe plane so that magic does not work on it. Now you've removed the best way to get through the door, magic. Now they can only pick the lock, or break the door.

Make the door adamantine, now it has hardness 20. If you make the door exceptionally thick it would lots of hp and would take quite a long time to break through. Instead of a traditional "lock" it requires a specific artifact (artifacts being immune to antimagic) to open the door. There is no locking mechanism to disable.

As good measure, include a couple of adamantine golems that lay dormant unless you try to break through or enter the library without the artifact. Include a magic mouth (spell) that instructs them (upon detecting anyone) that they must have the key or face "the wrath of the guardians". *Note, the area in front of the door should be big enough to accomodate the adamntine golems also within the dead magic plane.

[Artanthos]

The door is a magic item that only activates when the required trigger pieces are used in the correct manner. When the door activates, it becomes the portal.

Knock does not have the ability to trigger magic items. Breaking the door destroys the portal.

[paul1612]

Thanks those are pretty good ideas - I think I'll go with Claxon's dead magic zone as it fits my story the best.

[Claxon]

Let me add something, because I just reread my suggestion. You can't use magic mouth in a dead magic zone. Not really important, literally have if carved into the adamantine door instead.