Stages will be unlocked based on character’s level.
When the previous stage is passed, the next stage will be unlocked.
Stronghold: Every stronghold has around 15 stages. A new stronghold will be available every 10 levels.
Each stage has 1-3 waves of monsters. BOSS will also appear.
Defeating a wave of monster can obtain EXP, silver, S Ability or materials.
Stage clear cheas will be given when a stage is cleared. You will find EXP, silver, Vitality or coupons in it.
You can pick one chest out of three every time a stage is cleared.