Every time they succeed in slaying another unit or surviving a round, experience points (EXP) will be granted to reach the next level. Once the threshold is hit, the hero will be experienced enough to be granted a promotion to another level. Higher levels allow it to wield all items within that level requirement and below.
Surviving a round will grant the minimum amount of EXP. Different EXP rewards will be granted as a function of the slain unit. Basic units will reward the least, while heroes will provide twice as much. Due to their godly nature and being an important part in winning the match, a slain god will grant an automatic promotion to the next level, skipping experience and SAP requirements.
Once the level experience cap is reached, a player may spend SAP to grant the hero access to another level. If doing so, it will be granted a boost in selected attributes and recover a fraction of its lost HPs. A player may spend SAP for this even if the unit is exhausted.