Ibris Monastery was founded ages ago as a place for clerics to practice and conduct exorcism rituals. They protect local people by fighting off and sealing evil spirit.
On the day that the disaster happened, as the evil spirit’s power was far beyond that of the clerics, what they could only do was to temporarily weaken the evil spirit at the cost of their lives. until someone finds the way to eliminate it. They also sealed the Holy Vault, where there were ancient holy artifacts and may had the weapon to fight off the evil spirit.
You, as the destined people, have to find the way to enter the Holy Vault hidden inside the Monastery and find the artifacts that could help defeating the evil spirit while it is in the process of gaining back its power before it’s too late.