Just a fast description on warrior types all factions share:
Tanks: Frontline warriors that can take a lot of damage and halt enemies forces advance, will normally be slow but have a good attack power. Ex: Orcs, Trolls and Knigths
Blitzers: Close range warriors, with very good damage and speed, but low armor. Better used in hit and run tactics or mixed with tanks, perfect for flanking enemies and get to their rear troops. Ex: Fairy, Barbarian, Lamia
Long range: Units with different strenghts and weakness, but they share the ability to attack from long range. Better used behind the tanks or in guard posts not accesible by the enemy. Ex: Archer, Warlock, Wizard
Support: Units that can cast Healings, buff and debuffs, they migth belong to any of the previous groups but most are dedicated rear troops. ex: Cultist, Church Maiden, Cleric