Past:
Between 200 and 300 years ago, and with The Demon King once arised, all villages, towns and kingdoms, were started to being attacked. It all began from the villages positioned more closer to the demon kingdom, quickly spreading death over the lands, with villages falling aparts and terrains being conquered.
One of this villages was Merrifog, but when the demons were sent under the command of the Demon King, they were counterattacked by guards of the village. This counterattack failed, as the demons easily killed almost them all, and then they continued with the village, killing everyone, men, women, and children, all by the same fairness to death. The demon warrior were the one killing, and the demon mages were the one spreading the spell the Demon King gave them, teached them to learn for the conquest. This spell was casted on everyone, transforming them into demons of all kinds, but they received orders from their general to seal them for being too weak and irrelevant. The demons took everyone from the village now demons too, leading them far away, into a mine they found. Once inside, the demon mages created a hole with magic, in the deep of the mine, and the warriors pushed the villagers inside. Once all villagers were inside, the mages sealed the hole, and all of the demons left.
Present:
Years passed, now becoming 500 years when the Demon King arised from the ashes of the last boss, as the Demon King, was the second phase of the last boss. The time it took to change in it's second phase, was a strategy for guarding everyone down, before striking.
Future: