Each of the 21 elements is most fundamentally an aspect of the human psyche. The gods have so much power in their own precepts that a single aspect overwhelms each of them and significantly limits their free will. Although Mulcarn was slain, his precept could not be destroyed.
The essence of Ice is nostalgia and a reactionary drive to return this to how they used to be (or in more often cases an exaggerated misremembered ideal of how they used to be). As the Sphere of Ice had spent all of its time from its creation until the death of Mulcarn with a divine avatar, it yearned for a return to that state. Mulcarn himself was dead and gone, so the sphere of winter had to find someone new to replace him. As mankind does not remember the time before Mulcarn's fall and does not realize how this evil god clung more tightly to his original nature and refused to fall into such depths of evil as his allies, their memory of the God of Winter is one of a great terror that rules the entire world. This is the past the precept (I'd rather call it a Numen, but Kael has never used that term) drew Auric to wish to recreate, thus creating a new God of Winter far more malevolent than the old.
Auric Ulvin is ethnically Illian and grew up in an Illian town, but was far from the center of Illian culture. Brigdarrow was one of the most distant boarder villages of the Illian empire. The closest Illian city was Gelu, which it would take a minimum of 12 days to reach on foot. It was closer to the Ljosalfar city of Cerrolan, although still an 8 day walk away. It was only a 2 day journey away from the Whispering Wood, which held the Well of Shadows and the Once Elven city of Barathrum.
The people of Brigdarrow contained many Illian customs (such as demanding a strict monogamy that required a widow or widower remain forever in mourning and never remarry) but The White Hand did not seem to have any influence there during Auric's childhood. There was one temple in the town, but it was devoted not to Mulcarn but to Danalin. This temple was near a lake sacred to the water god, and guarded by a Nuckalevee. This was after Danalin fell asleep and his beasts were driven man, but before Hastur had such influence that his only priesthood were the mad cultists of the Overlords. The local priest of Danalin, Father Prespin, was seen as a doddering old man but was very kind, gentle, reasonable, practical, and sane. The faith at this time (perhaps in part because their god was not around to provide real miracles) had a rather "god helps those who help themselves" philosophy. While insisting that miracles were possible they taught that Danalin was unlikely to miraculously intervene to save someone from his own stupidity, so we should be cautions to avoid putting ourselves and our loved ones in danger. They valued hard work, but were more laid back about it than the priests of Kilmorph. They are the kind of people who when bad things happen would just shrug it off and get back to work to fix things.
Auric did not grow up within the town of Brigdarrow proper, but on a farm on its outskirts. He was a very odd and awkward boy, and was thought to be cursed. He always seemed old and wise for his age and possessed a self deprecating affability that made him into a bit of local flavor instead of a true pariah. He was a natural magical prodigy similar to Henri Ghouls or Laroth, but whose skills do not seem to have been initially focused on only one sphere. Without any training he was able to always feel the presence of mana sources like Tarch's tower, and even instinctively threw lightning to protect himself during a goblin attack. Once he began training under Talia he learned as much in one night as had taken her many months, and she had been the most talented adept at her Ljosalfar mage guild. He was probably chosen by the Precept of Winter because he was naturally the most magically inclined boy born in generations, and likely the most powerful Illian mage ever born.
(I have no basis for this, but I personally like to think that in addition to Illian heritage he was also a descendant of Kylorin. What would be really cool is if Epona's next reincarnation was as the Illian girl Harna, and if Kylorin took on the identity of Joshua Ulvin in order to life a simple and peaceful life with her there on the borders of Brigdarrow. A life of such anonymity spent with his beloved is what Kylorin most desires, and he'd gladly refrain from using magic (or even teaching magic to a highly talented son such as Auric) to maintain his cover among a people who would hate him from slaying their god. Technically Ashes of Brigdarrow does not give proof that the Ulvins died when their farm was burned, but it does seem odd that Kylorin would not have defended it better if he were Joshua. I suppose it is possible that Joshua was away and as he did not return in time to save Harna he left to find her next incarnation, but it would seem cruel for him to leave his 16 year old son an orphan during the decades while he waited for Eve to be mature enough to marry again.)
In the version of Ashes of Brigdarrow Kael shared with me, Auric read in the Library of Barathrum an account by a Priest of the Hand who had been there when Mulcarn was slain. This has probably changed since then though, as I pointed out that this was an anachronism. All the works in this library were written in the land of the dead and taken by the Gossam brothers when they escaped from Laroth centuries before Mulcarn's death. It is quite possible for him to have read accounts of Mulcarn's summoning into Erebus while he was there though.