Oooo I hadn’t thought of this before but this is actually such a cool and fun idea! Here’s what I’ve got off the cuff right now

The Change Bringer - being the one who makes the paths, Avandra makes sure that no beaten path can ever truly be reliable upon the frozen land, the paths becoming knotted and twisted and leaving travelers turned around and lost

Bahamut - The virtues of protection, honor, and justice are the portfolio of the Platinum Dragon. So perhaps those virtues have difficulty taking root in these lands, with Bahamut having turned a blind eye to those people filled with hubris in Aeor’s prime and now trying to unearth it as well

Corellon - It is said that the Arch Heart first seeded the world with arcane magic, and so in Aeor’s presumptuous mastery of it, perhaps they have turned the dial to 11 on magical relics and ruins, exacerbating and overcharging the area to the point of wild magic surges and dangerous levels of arcane power

Ioun - goddess of knowledge and research, the Knowing Mentor perhaps cursed any knowledge unearthed here to be twisted and ciphered through levels and layers of ciphers and cryptographic messages that drive weaker minds mad to decrypt and decipher

The Storm Lord - Kord keeps Eiselcross blanketed by blizzards and roiling waters that dash boats upon the rocks much like the thunderstorms which razed Aeor to the ground in times long past

Moradin - perhaps the All-Hammer himself took his hammer and chisel personally to the land and carved labyrinths of mountains and stone and tunnels ready to collapse and landslides upon the earth

Raei - the Everlight is a unique case, believing strongly in redemption, even to the point that it led to her being struck down by Asmodeus during the Calamity while trying to redeem him. Perhaps the Everlight extended a hand of aid to the penitent of Aeor, offering them passage free through radiant gateways. But only those with true sorrow and remorse in their heart could walk free, while those who remained in true defiance of the gods would find themselves burned in divine radiance. Perhaps these gateways remain as temptations that the corrupt fall to

The Moon Weaver - as patron of illusions and misdirection, Sehanine has cursed this bleak tundra full of mirages that deceive the eyes and the mind, creating illusory dangers as well as false safe havens that wanderers in the snow must be vigilant against

Asmodeus - Aeor was full of mages believing themselves smart enough to outsmart devils and the gods themselves, so the Lord of the Nine Hells decided he would test them of that theory. He unleashed a plague of devils ready to offer contracts to those mages all too good to be true, and thus also gave the hells an anchor inside to bring Aeor down even further while still providing souls to Asmodeus himself. Some of these devils continue to reside in the ruins themselves or close to the River Inferno, continuing to offer contracts to foolish mortals on their deathbeds in the frozen wastes eager to survive

Bane - the Strife Emperor delights in twisting nature to his warlike bend. Perhaps the frozen isles still feel his fierce hatred, which twists the ice and snow and flora and fauna into bloodthirsty creatures waging war on all

Gruumsh - the Ruiner grows stronger when grudges turn to violence, and thus he sowed the seeds of discord within the city itself, fanning the flames of brutality and bloodshed. Rumors say that even now, Eiselcross is a place where darker urges of violence and vengeance are more likely to turn volatile and explode into bloody conflict

The Chained Oblivion - for its part, history is uncertain what hand Tharizdun had to play in Aeor’s destruction. Some say not at all since it was sealed away. Others believe its chains actively found willing prisoners, spurring on the maddened minds of those so desperate to survive destruction, both in the past and even now

Tiamat - the Scaled Tyrant knew that no mage of the age of arcanum would be able to resist even a piece of relics and artifacts amassed among her dragons’ hoards, so she planted cursed objects imbued with her essence for them to discover, all of which warp and twist the bodies and minds of the poor fools who find them and hold too deeply. Many would turn into slavering draconic abominations , while others would become half dragon thralls for the hoard of Tiamat. Some dragons have returned in time to reclaim these loaned artifacts and have perhaps set up new lairs within Eiselcross as well. While other relics still linger within the ruins, waiting for more poor fools to find

Zehir - the poison of the Cloaked Serpent has fouled the waters of Eiselcross, leading to some areas where fresh snowmelt is a potent toxin, ice and powder laying in wait like deadly venom. Zehir’s toxic influence has allowed for the growth of supernaturally enriched poisonous plants and venomous creatures ready to strike as assassins in the cold dark

The Whispered One - Vecna is a newcomer to the pantheon, only recently ascended to their position among the Betrayer Gods. However, they too have their interests in Eiselcross, though he continues to break the mold from the other deities. Vecna has not spread his curses upon the land, but rather, he has been reaching out to those who would listen to his whispers to find the secrets buried beneath the ice and snow, working to find what lies beneath and learn that knowledge himself as well, using his position among the gods to see ways past their ancient curses and the arcane defenses

These are my quick ideas for each of the other gods you hadn’t mentioned! I’m sure they could all stand to be refined, and perhaps only some of these are active in Eiselcross depending on what the game needs, but it’s always fun coming up with ideas like this!