Classes and their passive abilities or traits (also applies to some regular units found in campaign)
Alongside their elemental affinity, some units have a role or class and special passive abilities. Listed below are some of the common traits encountered in the game.
Armored
Upon receiving Rogar Stonecrusher, the first hero you will have obtained, you will notice that when enemies hit him with physical attacks it will have a clinking sound and have the message "Armored -X" appear. This means that amount was reduced from the supposed attack. Being armored is a huge benefit against physical attackers. If the opposing team consists of a number of Armored opponents, it may be a good idea to go for magic wielding heroes. Although even when armored, some elemental bonuses can still go through so you may even defeat an armored opponent even with physical strikes. Armored units or heroes take increased damage from Lightning attacks and its respective debuff.
Warrior
Warriors often deal a lot of damage compared to other classes due to their raised attack power. Their skill set also tends to favor the offensive style.
Tanks
Tanks are tough classes who are there to soak up the damage for the team. These guys usually have the armored trait. Along with the innate toughness, they usually have a taunt ability to focus single target attacks to themselves.
Healer
The healer class is responsible for keeping the team alive and well. Although they may usually are on the weak side offensively, they can have their uses if used at the right time. Yasmin Bloom for example can do great damage on undead types since she also has a "Hunter" skill. The skill Pwn Undead does extra damage to undead so in fights against undead, she may be of use other than healing.
Flying
Flying opponents are easily spotted since they are off the ground. Flying enemies receive less damage from melee attacks but receive additional damage from any ranged attack. Flying enemies generally also have less HP but higher dodge chance.
Hunter
Some heroes have a trait called Hunter. These hunters do boosted damage to whatever it is they are hunting. For example, some heroes have the Tank Hunter trait meaning they deal more damage to tanks. Warrior Hunter deals extra damage to warrior classes and so on.
Race
All heroes and units fall under the few races in the game. The races are Beast, Demon, Dwarf, Elf, Goblin, and Undead. There are two more races, Mushroom and Spirit but there is only one hero on each of those categories. Some units with the hunter skill also give advantages to certain races. Demon hunter does extra damage to demons, beast hunter does boosted damage to beasts and so on. Aside from these, some events will happen that give certain races boosted Stats like more attack, HP, def, crit, etc. These events are random though and you should not rely on them too much.