does anybody have any tips for slaying the demon in the planer sphere quest ?

Haven't gotten to that point just yet. I have just completed putting the Golem back together, killed the Eye Tyrannt and saved the game. Sucks to have to be up at 6am ;(

Once I get to him, regardless of how much more I have to do, I'll post my own way of dealing with him.

Syl...

Those demons are tuff! Thank goodness for Autosave. Basically, I got lucky. I had my mage and druid summon creatures and kept my characters out of the area until the demon was sufficiently weak. It took around 3 tries for me. If you have any items/spells that protect against holding and confusion, use them. I only wish I had a scroll for paralyzation. Would have made it much easier. Good luck!

Mind you, you dont have to kill ALL of them. Just one will suffice, quest-wize.

What! There's more then one Tanarrii?? Damn, I just killed one and wen't back to the sphere hehehe. well my trick whas to send my fighter at it and overwhelm it with spells, sorcerer are nice for the sheer quentity of spell they can cast.. with a back up mage to breach its defense, it wen't kind of quick

I just had my Ranger and Minsc beat the crap out of it, no magic involved. Of course, they're both dual-weapon style juggernauts of death, hehehehe.

I had my bricks move close to the field of battle then sent my thief to take down any peripheral salamanders and imps I could backstab... unfortunately the demons can see invisible creatures (EVEN THOUGH I HAVE A non-detection cloak, what's the point of that cloak) Anyway, once I was spotted and my backstabbing spree was over I sent the bricks right at the demon. Killed him pretty quickly, but then I do have a Holy Avenger. (which wasn't much use vs clay golems, I might add... oops... should have put a point in a blunt weapon)

A point in flail never hurts...