
Index -> Playing the Game -> Types of Cards -> Unit
Units are denizens of Norrath that have been inspired or coerced to support you against the enemy. They have the same attributes as your avatar (attack, damage bonus, and defense) and they have health, though they are more easily destroyed.
When your units are at a quest that your opponent is attempting, he'll have to fight his way through them to apply an ability there. Units can be mixed freely with one another in any deck, and with any archetype of avatar. (A few special units are Mage cards and represent summoned pet minions.)
When you play a unit, you'll have to select one of the two quests on the playmat.
If you want to raid your opponent's avatar, play your unit to a quest where your opponent has no units.
If your opponent has units at a quest, you can play units there and raid to clear them out.