I'm a new DM that is running an adventure with a vault protected by a Forbiddance spell with a password which the PC. One of the PCs is a Spiritualist and as such has a phantom. I'm looking for guidance about how to properly apply the Forbiddance rules to the phantom.
The phantom can exist in one of three main forms:
1) Shared Consciousness - The rules are unclear, but it would seem to fully exist in the material plane. It cannot be dismissed or banished in this form.
2) Bonded Manifestation - The rules are unclear, but it would seem to exist in the material plane yet require access to the ethereal plane. It cannot be dismissed or banished in this form.
3) Etheric Tether - This pulls the phantom out of the Spiritualist's consciousness and fully manifests it. It can be either dismissed or banished. In this form, it is treated as a summoned creature from the ethereal plane.
The phantom has two different kinds of manifestation:
a) Ectoplasmic - Per the rules, ectoplasmic creatures draw energy from the ethereal plane.
b) Incorporeal - Exist on the material plane with no connection to the ethereal.
After much reading, here's how I believe things should work when the Forbiddance area has a password and the password is known to the PC. Please correct any mistakes:
No matter which form the phantom is in when entering an area affected by Forbiddance, the phantom will be unaffected. The only question in my mind in this situation is whether the ectoplasmic manifestations would be affected since they draw power from the ethereal plane, thus opening up the ambiguity of whether this is only when being formed or is a continual requirement.
While inside a Forbiddance area, a Spiritualist cannot switch from #1 or #2 to #3 since this would require summoning the phantom from the ethereal plane. Since the rules don't specify #2 as being treated like a summoned creature yet the description details using substance from the ethereal plane ("a spiritualist can pull on the consciousness of her phantom and the substance of the Ethereal Plane to partially manifest aspects of both in her own body"), it would seem that a Spiritualist cannot switch from #1 or #3 to #2 either since this would require access to a plane that is blocked. In addition, it would seem that a phantom could be switched from ectoplasmic to incorporeal but not from incorporeal to ectoplasmic as this would require drawing energy from the ethereal plane.