Class

All heroes have a class. Class determines what benefits a hero gains as he levels up as well as what abilities he can learn - it may also grant specific passive traits. Heroes can upgrade to better classes when everything is going well, or they might change to a worse class when life is going against them.

In essence every hero multi-classes, their class determines their current stat growth and what abilities they can learn but they are able to retain old abilities. The AI is designed so that if, for instance, Inatha is rising and frost is crushing the world then Mage Guilds will begin to research fire spells and Orders devoted to flame will arise with great pull to heroes - you may see various heroes enlisting in the order to learn its secrets before moving on to other classes. They are unlikely to re-train that ability as public knowledge of SNOW_THREAT rises, giving an AI value boost to retaining it.

Berserker
The Berserker is a Tier 1 Warrior that forgoes defence for overwhelming offence.

Crusader
The Crusader is a level 1 Warrior and Leader who will stop at nothing to destroy the darkness.

Knight
Knights are an upgrade Warrior class that can occur when an adventurer completes a mission for a nation and is awarded by being Knighted. Knights are the only hero that carry the shield of their nation, and are easily recognizable. They are defensive minded warriors and will also often become army leaders late in the game. Knights act as Champions of a nation, and are the earliest champions outside of the starting set for a scenario that a player will often see - most other classes can become champions but only after completing epic quests for a nation.

Warrior
Presumably the basic martial class.

Sorcerer
A sorcerer is a Tier 2 Sage, adept at Battle Magic.

Battle Caster
The Battle Caster employs his spells to devastating effect in the midst of combat, often for his own gain.

Bounty Hunter
Bounty Hunters are the amoral equivalent of a Warrior.

Sellsword
The Sellsword is a basic Warrior class that prioritizes Strength and Command. It really is the player's favourite class to see because Sellswords rarely go for any of the more dangerous and rewarding quests, instead being content to work on easy quests for gold. They will never go for an Epic Quest unless a nation has sponsored it with gold. They tend to work alone, and form friendships less easily than other classes - both good things for the old one. When a Warrior class has been disheartened, and has low willpower, it may change into a Sellsword.

Thief
Thieves are skilled at stealth and plunging into ancient ruins, but less so in combat.

Inquisitor
Hunter of Heresies and Sword of the Faith. The Inquisitor spends his time seeking to purify the faith and stamping out renegade cults. Nothing is as dangerous for nearby heroes as a bored Inquisitor.

Templar
Templars guard Priests and Inquisitors on their hallowed duties, helping to spread the Faith by keeping the Faithful alive. Templars who fail in their sacred duties seek Penance, their faith in themselves and their God challenged.

Priest
Earthly Vessels of the Divine Will, Priests spread the word of their Lord, construct new Temples, and seek lost Holy Sites in order to better bring their Lord's blessings on the world.