Way to stop Dismissal?

[Aluvial]

Well, I have Spell Immunity, and can take 4 spells.

I'm picking Dismissal, and then I need to pick 3 other 4th level or lower spells.

I am trying to protect a marilith (as if it needs much) but I have a canny group with access to the Spell Compendium to defeat.

Aluvial

 

[DumbPaladin]

Spell research something nasty that binds a creature to the plane it's on for a limited time? Give it to one of the marilith's casters?

 

[AuraSeer]

Use the old DM standby and give her a custom magic item. Make it work like an improved dimensional anchor, giving immunity against external dimensional effects but still letting the wearer use her own spells or magic abilities.

This effect might not be something you want the PCs get their hands on once the wearer dies. Since the wearer is a marilith, there's an easy solution to that: it's a set of bracers that only works when all six are worn. A humanoid wearing two of them might just get a partial bonus, like +4 on saves vs. dimensional effects, or some such.

 

[Sorrowdusk]

Its a raid in DDO but they have Boots of Anchoring which are required, because the fiends may try to banish you back to your own plane during the raid.
Boots of Anchoring - DDO wiki

So I would imagine you could have an item enchanted with a constant Dimensional Anchor effect or the like.

 

[Empirate]

How about wearing Dimensional Shackles?

 

[Runestar]

Spell Immunity...

I get to pick 4, Dismissal, Dispel Evil, ?, ?

Can you think of other spells that Dismiss a creature back to its plane?

Aluvial

EDIT: I can't take Dispel Evil because it is 5th level.... hmm...

Dismissal's a 5th lv wz spell, so spell immunity won't always work.