Bringing Sorten the Sword of Air

My party is hip deep in the Sword of Air campaign, and I'm getting to the point where I could use a little advice.

To make a long story short, there has been some fantastic roleplaying, a doppelganger posing as a PC, and about 2 1/2 years of backstory and the party has been split. We play Swords and Wizardry, and each player has a main character and several backup characters.  We tend to hit the B squad when we're short a player for the main portion of the campaign, as it helps keep them in line as far as levels go.

A pair of doppelgangers working for Kayden had the party cleric jailed in Bard's Gate (unjustly) once they found out they had acquired the Sword of Air.  One replaced the cleric (and the player gleefully played the doppelganger for several sessions!) and it was his duty to get the party as close to Kayden's Mansion as possible, then steal the Sword.  Which he did, quite succesfully, at least until he got caught in the swamp outside Kayden's Mansion.  Kayden himself made an appearance as the party fought over the Sword (still not realizing the cleric was a doppelganger).  The groups halfling thief snagged the sword and escaped from what turned into a drop-down "Avengers Civil War" type fight between the good guys who all had different ideas of what to do with this incredibly powerful sword!  Everyone except the thief was captures and put into the "Character Killing Session" module.

The thief, meanwhile, took the Sword back to Bard's Gate where he released the real cleric and picked up another one of the main characters who had been semi-retired.  They have decided to take the Sword to Sorten to have him ... uh... Sorten things out (ba-dum-bum). 

 

So!  My question.  What does a 20th level magic user do when the party comes to him bearing one of the more powerful artifacts in existance and says "here, help us with this?"

Bear in mind that Sorten a) Knows about the Sword and Aka Bakar via the retrieved Shaghaspondium, b) knows that Kayden (and Steve) want the sword c) has no idea of the good or bad way to destroy the Sword except what few clues are in the Shaghaspondium

Treat it like the one ring?  Sorten knows he can't touch it - for fear of what he could become with the artifact - and while the party is trying to destroy it - he can keep Kayden busy (or pretend he has it so Kayden attacks him)....

You know if you wanted to play it up he could provide some kind of aid to rescue the other party with - perhaps a portal and a trick or something :)