[SixOfSpades]

In my experience, the Minor Avatar's Spear allows no Saving Throw vs. the Imprisonment, there's simply a pretty small chance per hit that the spell will fire. A scroll of Protection From Magic will be of no help, since it does not block magical weaponry--but by the same token, PfMW will save you. Tough luck for a Ranger/Cleric. Also, Mirror Image will postpone the killing thrust--again, tough luck for a Ranger/Cleric.

The good news: You can buff up with whatever you want, since neither the Avatar nor the Priestess will Dispel or Remove it. Her "Shark-Father's Swift Blessing" is 17 buffing spells (on her) and a Greater Malison (on you). Assuming you've got the Boots of Speed, you can run the Avatar around in circles all you want until the GM (and the Priestess's True Sight) wears off.

The bad news: He's hit only by +3 weapons and up, which means you're stuck with Sunstone Bullets if you're trying to outrange him. Forget about poking him with a 2-handed weapon and running away--his Spear is just as long. But there was that Staff of Thunder and Lightning you picked up in Spellhold....with a chance of Stun on hit.

My Advice: If you're playing No-Reloads, forget the damn Minor Avatar. Be content with the good Cloak and let the sharks keep their cheese.