A backline consists of characters in a team positioned furthest away from the enemy. It is usually populated by support roles such as monks and ritualists. This line may also include support necromancers, such as those who use Blood Is Power, and other professions who use support builds. The usual distance of the backline from the frontline is the the spellcasting radius.
In builds that have units who do not need to stay in spellcasting radius, it is possible to have a second defensive line after the backline. These characters are often Heal Party spammers, orders necromancers, or bonder monks.