(Urban fantasy + supernatural powers + extraordinary beings + action and power progression + smart characters)
Enter a secret realm and successfully complete its mission to claim a reward.
If the mission is failed, the secret realm sinks into the real world, hidden away and undetectable.
If a "chosen one" from the real world wanders into a hidden secret realm and successfully completes its mission, the realm will be erased completely.
But if the "chosen one" dies and fails the mission, the realm's most powerful supernatural beings or monsters can cross its boundaries and enter the real world to have some "intimate" interactions with people.
