Level

Level is a measure of a unit's overall abilities within their current class. A unit in their base class has a maximum level of 20. Promoted units have a maximum level of 20, unless they have used an Eternal Rune, in which case it increases to 30. Enemy-exclusive classes have a maximum level of 50.

Changes in level
A unit's level increases by 1 when they gain 100 Experience Points. This triggers a Level-Up, which may lead to units gaining stat increments, based on their growths.

After using a Promotion Rune at level 10 or higher, a unit's class will change to the selected promotion option. Their stats will change depending on the choice made, and their level is reset to 1.

A Reverse Rune can be used to decrease a unit's level by 5, provided they are level 10 or higher. This will cause 5 "level-downs" (which reduce stats based on growths instead of increase them), but will not make units forget skills they would normally learn at a higher level.