"Please forgive my companions their hesitance, it's truly an honor to meet you. Quaryl Tellasarim, I presume? I am Ivaebhin Aelorothi, of the Evermeet Aelorothis."

"A pleasure. I have been trapped here for some time, ever since the city fell, with little company."

Also inside his chamber, not visible from the entrance, are two statues of mummified mind flayers. 

"There's so much we should ask you, we're fellow seekers of truth, trying to work out whether the perpetual winter over Icewind Dale is the work of a misused or malformed mythal - but first, are you aware of the magical edgelands anomalies all over the area? Or the doppelganger mages approaching?"

"Learning is the most valuable reward." He waves a hand, and a few books drift over towards the party. "These discuss the weather-regulating aspects of Myth Drannor, may they grant you insight."

"As for the pulled threads, they exist as a consequence of some invasive research I have been performing, on matters of arcane permanence. The Weave will repair itself in time; Mystryl knows what is occurring here. Those threads will be snipped or sewn back in, and those that are trimming the burrs from the Weave will be richly rewarded."

"Your pursuers are at the entrance." He chuckles. "Not doppelgangers but ultroloths. An understandable confusion, perhaps the batrachi cultivated their spies and assassins from that fiendish stock. Please excuse me for a moment."

He vanishes with another teleport. 

"Those were ultroloths? Three of the greatest of the Greater Yugoloths? We need to help him somehow, they're inherently magic-resistant but maybe -"