Hell contains ancient demonic artefacts. These unholy items are very powerful and not affected by time. They are well guarded by powerful demons. The hell is guarded by a keeper. This entity can release a "Time Traveler" upon intruders ; A strong and invincible creature that has the ability to move through time while taking someone with them. You're summoned by a mysterious entity who created a group named the "Hell Diggers". It appears that the leader of this group is the demonic lord of greed and chaos. As a demonic lord, the Hell Digger's boss can create a thick myst to hide his servants' schemes from the keeper. It can only last for a certain amount of time before it vanishes.