Empowering your dragons makes them stronger in battles (life points & damage dealt) and increases the maximum level they can grow to, as well as giving them a special aura.
 
A dragon can be Empowered to a maximum of 5 stars.
 

Empower Level

Maximum Dragon Level

1 Star45
2 Stars 50
3 Stars55
4 Stars60
5 Stars70
 
 
Note:
  • Empowered dragons will also give you more Dragon Master Points.