Sumigo - The Dickening

Lady Vagriel and her bodyguard Analynn come to an abandoned cemetary, Vagriel goes into the old church alone where she finds a secret stairway going down. There she finds an old underground crypt with a large sarcophagus and an altar inside. After making her way to the altar she is confronted with a skull possessed by an ancient spirit.
The spirit convinces Vagriel to strip and recite a spell from a book sitting open on the altar. Lady Vagriel does as instructed, but this is the beginning of the end for our hero as her actions unwittingly unleash.