You can upgrade the star rank of heroes with a certain number of exclusive hero shards. An extra effect bonus will be given to the squad skills when your hero has reached a higher star rank.
The maximum star ranks are different according to the hero's rarity.
- Rare heroes (blue): 5
- Epic heroes (purple): 5
- Legendary heroes (Orange): 8
Exclusive hero shards will be consumed when upgrading star ranks. You can also use the universal shards to substitute the insufficient shards.
| Star Level | Required number of exclusive shards |
| 1 | 10 |
| 2 | 20 |
| 3 | 35 |
| 4 | 50 |
| 5 | 75 |
| 6 (1 Red star) | 100 |
| 7 (2 Red stars) | 125 |
| 8 (3 Red stars) | 150 |