UnderDark : Defense v2.1.6

What's new in version 2.1.6

### Update Notes

1. New heroes, Necromancer and the Skeleton who wants to be a Hero, have been added.
2. The Season Pass has been reset.
3. A new Bingo event has started.
4. Stages have been expanded.
5. In the cooperative dungeon, if the opponent leaves, it will be treated as a loss.

### Balance Adjustments
1. The higher the hero grade, the greater the increase in attack power and health with each level up.
2. The time to acquire sweep tickets has been reduced.