I just completed the Mythwright Scholar achievement and was very surprised about Zommoros's Research Notes (minor spoiler comming). Let's go over the clues.
I'm not really sure what happens with Qadim after his defeat, but it seems, he survived the battle in some strange way, and I guess, he is not very pleased that we spoiled his plans. So we might have a reunion with him soon or later. Anything else would not make much sense, because why else would you let him live?
And then there are the Research Notes:
The wing and the achievement gave us some clues about Zommoros and the Djinn; in most particular how Djinn do think about the world, other creatures and the elements. I think it's suspicious that Isgarren is beeing mentioned in there. I mean: Why is there a reason? It could have been anyone else. Someone more known characters or someone completly new. But for reasons: It's Isgarren. Maybe to bring his name back to the minds of us players (?)
From the people of Garenhoff we know, that Isgarren sent Elements to the village to protect the villagers and the tower.
We really do not know, what kind of person this Isgarren is. Considering his releationship to Elemental-Creatures and his old age it's possible that he is another Djinn (maybe a powerfull Air Djinn in disguise-> flying castle). So, if Qadim still is interested to add excotic creatures to his collection, he might visit Isgarren in the next raid - for some of the Wizards experiments or for Isgarren himself.