The Chilfos
Strengths: Gigantic forces that are cheap to purchase, swift growing population and upkeep
Weaknesses: Highly susceptible to fire, not at all durable.
Faction Bonuses/Penalties: Bonus in snow, penalty in all other terrain types.
Rival Factions: Order of the Wizzrobe
Cordial Factions: None
Starting Position: Number 6
Time has forgotten that long ago, the Order of the Wizzrobe was no secret society of magicians but a small society of scholar's open to all, that would travel the length and breadth of Hyrule in order to uncover the mysteries of the world and especially of magic. As the group travelled across the mountains of Peak Province in search of the mysteries of the north, they came across an abandoned Yeti child toying with glaciomancy, the Magic of Ice, creating animated friends to sit at his side. The curious Wizzrobe took the child in to study his new form of magic and to understand the perplexing nature of the Yeti, but something dark festered in the heart of the child. As he grew, the Wizzrobe slowly looked past the innocent exterior and noticed the evil that grew within his heart, with deep mistrust beginning to form in their own hearts. The mistrust was not easily held back, causing the Yeti to feel betrayed and turn on his adoptive family, killing a number of them before fleeing into the Peak Province. The Wizzrobes hunted him down, locking him away within the heart of the mountain range, and forever changing their attitude to the teaching of non-Wizzrobes; No more of their deep secrets would pass to those not of their species, and nor would any discover what danger lies at the heart of Peak Province.
Sorry, wrote this when tired so not the greatest of tales.. but anyway! The Chilfos are the only faction from the icy north which can ever work, due to the fact that they could take a whole number of shapes and sizes, and also that they are far creepier a foe than any other. My thoughts regarding the Chilfos is that their forces would be huge, but also that as they conquer lands of their foes their forces will adapt. For example, if a force of the standard Chilfos conquered a Goron territory, then a Goron-esque Chilfos shape would become available to make use of, showing their adaptations to whatever foe they have to conquer.
Also, many have complained that it would not make sense for the Chilfos to fight across deserts etc, which is why I gave them a penalty in all terrain types bar snowy areas. Not only that, but I have come up with an idea which should hopefully provide a decent explanation for how they can cope.. When Chilfos are in territories which they do not own, they experience a large rate of attrition for their forces in the form of people beginning to disband from the army (like how it happens in the Crusades in standard Medieval 2 Total War). However the player is capable of purchasing Chilfos units through the Mercenary tab, this would essentially represent the artificial ice-fall caused by the controller of the Chilfos to replenish their forces. This would make invasion a risky and expensive venture if you are not careful, adding another dimension to playing as them.
I expect Freezards and those White Wolfos from Twilight Princess would be part of their forces.