Empyreal Orb
From Unofficial Fantasica Wiki
Use Empyreal Orbs to permanently increase a 12★ unit's maximum level.
By default, the maximum level for a 12★ unit is 240. Empyreal Orbs can be used to increase the unit's maximum level by an additional 40 levels. Each Empyreal Orb increases the unit's level cap by one level, and a maximum of 40 Empyreal Orbs can be used per unit.
Prismatic Orbs can can be obtained from Login Rewards, Events, and Bonus Rankings.
Other Level Break Items
For 11★ rarity units, please refer to 
Aurora Essences and 
Celestial Orbs.
For 10★ rarity units, please refer to Aurora Essences and 
Prismatic Orbs.
For 9★ rarity units, please refer to 
Ichor.
For 8★ rarity units, please refer to 
Soma.
For 7★ and under rarity units, please refer to 
Ambrosia.
