frankthedm said:
I say once the anchor is dropped, the recipent is not going anywhere. Maybe i am just a mean DM who likes to cut crafty players off at the pass, but it is hardly fair for a demon to be deprived of its teleportation and still be vulnerable to banishment if the fight turns ugly.
This aspect hadn't occurred to me: that depriving the demon of its teleportation ability should be balanced by
dismissal being ineffective.
The confusion, on my part, was that one spell said one thing and another spell said something else. Normally, I can make determinations based on the wording of the spell, or at a minimum, by looking at the spell level (the way that
daylight trumps
darkness and
deeper darkness).
The
dimensional anchor says it prevents planar travel, but I considered that the travel it was referring to did not include involuntary travel. For example, if a deity's avatar enters the Prime Material plane and is destroyed while under the effect of a permanent
dimensional anchor (no argument about how this is accomplished, please!), when the avatar is destroyed, does it reform on its home plane? (Note that this is rhetorical. I don't really care!

)
Anyway, the answers here -- as well as a couple of answers on the RttToEE forum -- have convinced me to rule that the
dismissal is a wasted spell in this situation. (But a
dispel magic first might drop the
dimensional anchor, allowing the
dismissal to work. I didn't describe the bebilith as being covered in a green aura, so I will probably make that description change and then let the PC decide whether to cast
dismissal. Maybe they'll take the hint and use
dispel magic first.

)