Light gets 30% damage bonus vs Dark units, while Dark gets 30% damage bonus vs Light units.
Boosted damage vs Light
|Light Hunter: Boosted damage vs Light Enemies. The multiplier [1.5x/2.0x/2.5x] of the boosted damage increases with the rank (I-III) of this trait.|
Overlord Executum is a Light Hunter.
Check out the sub categories and the Light Heroes page for more.