The army lists are set, although not to any specific background. They are mix of 'traditional' factions, and some unique lists based around Pendraken's fantasy army ranges.
There are twelve armies available;
BARBARIAN MEN
Barbarian men are savage tribes of primitive humans who are as rugged and wild as their homeland. They fight alongside an array of fearsome beasts and monsters.
DARK ELVES
Dark elves have made the underground realms their home, and come to the surface to raid and make war. Their powerful magic and skilled archers fight alongside monsters of the underworld.
DRAGON MEN
Dragon men hail from fertile feudal lands. Their armies are filled with ranks of armoured knights and warriors. They are ruled by dread chromatic dragons who rule as terrible kings.
ELDRITCH VAMPIRES
Eldritch vampires cast their dark rule over stygian lands of mountain, forest, and swamp, where subdued folk are dominated to serve their twisted masters alongside all manner of undead horrors.
GOBLINS & ORCS
Goblins and orcs are vigorous, fractious tribes who live by hunting, raiding, and war. Their tribe queens and war chiefs drive great hosts of warriors and monsters into battle.
HIGH ELVES
The high elves are ancient and powerful folk, with skilled archers and magic users. They count dragons and elementals among their monstrous allies.
HILL DWARVES
Hill dwarves are the living embodiment of stoicism. They seem almost carved from the rock of their homelands. Their warriors are well armoured and fight alongside powerful artillery and monstrous elemental creatures.
LIZARDMEN
Lizardmen dwell in vast jungles and rain forests, where their semi-aquatic folk thrive in the abundant life-energies. The lizardmen and their newtmen cousins take to war alongside forest beasts of all kinds.
SAMURAI APES
Samurai apes inhabit a mystical island that has yet to fully form. They are masters of war who are innately linked to the chaotic elemental energy of their homeland.
TAURIANS
Taurians are centaurs and minotaurs who dwell in a land of mazes and labyrinths. Their tribal city armies are savage, primitive, and powerful.
UNDEAD
Undead inhabit a sour and wasted land where no life survives. Their armies are filled with skeletons and the recently dead, and are commanded by vampires and necromancers.
WOOD ELVES
Wood elves are fickle and wild folk from the woodland realms, and like their kin are master archers and spell casters. Great eagles, forest elementals and the feared arboreal dragons are their allies.
Within each army, there are many units and troops to choose from, and these can be further modified with 'optional upgrades'. These have been designed so that they will allow you to tailor your army to your specific fighting style, rather than to generate an 'optimal build'.
It means that no two armies should ever be quite the same. For example, you could build a Barbarian Men army that is a nomadic mounted force riding into battle on bisons and mammoths, or a mountain tribe of infantry archers, fire elementals and flying icarusi owl men.
There's also some fan-made 'Game of Thrones' lists in the SSQ ezine here:
http://craigarmstrongonline.org/wp-content/uploads/2015/03/SSQfinal1.pdf