Ideas for handling a Shadow Demon's attempt to interfere with a vision?

[KrazyHades]

First off, though I don't think my players frequently read EnWorld...Isra, Moroch, and Sulderis, STAY OUT! You'll like the surprise better that way
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Here's the situation: the Neutral party cleric (rebuker) is coming up on a major holy day. He is going to walk off into the caves and meditate, where he is (though he knows it not) going to have a vision from Jergal asking him to act as his servant and agent in the mortal world.

However, there's a catch! Another member of the cleric's order, a high level druid who has secretly been consorting with demons, knows that the cleric is going to have some vision that will impede her plans. She is going to send a shadow demon to interfere. The shadow demon is explicitly ordered not to kill or permanently harm the cleric.

I'm looking for ideas on how to handle this situation. I don't want it to come down to a simple 'make a will save or be possessed', since that's both arbitrary and anticlimactic. I thought of doing something like a skill challenge, but I just don't think that knoweldge(religion) and wisdom and charisma rolls are really much more flavorful. I could just run the whole thing via roleplay, but I'd like to leave some of the power in the player's hands, so that he can roll dice and feel good.

Thoughts?

PS It's been ages since I've posted on EnWorld. It's good to be back

 

[SteelDraco]

I'd do a battle in the center of the mind thing. The creature comes after the cleric while he's meditating and enters his mind. The scene shifts to somewhere the cleric feels safe, but twisted to be dark and sinister. The shadow demon approaches in the guise of someone the cleric trusts, then jumps to attack. Maybe it has little minions to spice up the fight. The two battle in the cleric's mind with the winner controlling the body.

I'd probably also include some ability to control the dream environment, changing the terrain with Will saves or Charisma checks. Something to make it not a normal combat. Maybe the shadow demon keeps dragging the cleric back to his worst moments in life and taking the form of his worst enemies, and the cleric only knows what he's fighting when he cracks its facade.