Ubisoft is about to publish a detailed description of the Inferno and Haven towns. Everything is expected to appear on the official Web site tomorrow, but until then, here is a sneak peak:

Haven: "A feudal Holy Empire, the strongest realm of Ashan. (...) On the battlefield, Haven troops are known to be extremely resistant, relying more on the mighty power of brutal force than on the delicate art of magic. The heroes of the Haven faction will develop skills and abilities to support the hurricane of steel and fury that will rush into the enemy’s rank."

Creatures: 1) Peasant / Militia Guard 2) Archer / Marksman 3) Squire / Knight 4) Griffin / Royal Griffin 5) Priest / Inquisitor 6) Cavalier / Paladin 7) Angel / Archangel

Inferno: Demons are an alien pantheon of hostile monsters that are bent on conquering Ashan. Fortunately, they are imprisoned in Hell (a “dimensional jail” created in the lava core of the planet) and can’t exist for long in the material (surface) world, except when they are summoned by a sorcerer or when they can possess a mortal body.
On the battlefield, Inferno troops are famous for their insane brutality in both the might and magic fields. Inferno troops will rush into the melee, while creatures with magic abilities will disrupt the normal order of things to call for demonic reinforcements or to summon the fury of the fire element on their enemy.

Creatures: 1) Imp / Familiar 2) Horned Demon / Horned Overseer 3) Hell Hound / Cerberus 4) Succubus / Succubus Favorite 5) Hell Stallion / Nightmare 6) Pit Fiend / Pit Lord 7) Devil / Arch Devil

What is also interesting is how each town description is summarized: Haven is about "Law and Order", a shift toward the Heroes IV Academy, while the Inferno's motto is "Might makes Right", a saying that would have been associated to the Stronghold. Check out the new artwork released for these units at the Genies' Lamp.