Mercs are gradually Corrupted by the virus as they fight in both the Autoplay Mode and the Survival Mode. Once Corruption maxes out, the Merc can no longer be deployed. The maximum Corruption level varies for each rarity.

Corruption Level Accumulation

Autoplay Mode:

Rises with the time of deployment. The more damage a Merc does to an enemy, the more likely the Corruption level will increase. However, the level of Corruption does not increase with the boost in damage caused by leveling up and skills.

Survival Mode:

Rises in proportion to the quantity of Cores acquired.

Reduction to Corruption

The purchase of a Combat Vehicle can help reduce the increase of Corruption levels.

Corruption Reset

Cores can be used to reset the accumulated Corruption level. The amount of Cores consumed varies for each rarity.
Each time the Corruption level reset is performed, the number of Cores required for the next reset of the same Merc increases.

▼ Number of Corruption level resets and number of Cores required

Reset times Number of Cores required for each rarity
Legendary Epic Rare Uncommon Common
0 800 267 73 53 40
1 1196 399 109 80 60
2 1789 596 163 119 89
3 2675 892 243 178 134
4 4000 1333 364 267 200
5 5981 1994 544 399 299
6 8944 2981 813 596 447
7 13375 4458 1216 892 669
8 20000 6667 1818 1333 1000
9 20000 6667 1818 1333 1000
10 20000 6667 1818 1333 1000

*Stats may be adjusted before the game is released.

Merc Retirement

Mercs who have reached the maximum level of Corruption can be retired. After retirement, they can still be used as materials for leveling up and Fusion, but they will no longer be able to participate in game modes other than ranking events.

When a Merc retires, he or she will receive a Veteran Aura, and the attack power will increase by a random value. There are multiple patterns for auras, so find the one you like the most.