The 101st Heir of ShadowHilt and the sister of Erze. People call her cold-blooded for her unfriendly attitude, but she used to be all smiles when she was around her beloved sister, Erze. Seria always felt sorry for her feeble sister and was overprotective of her, without realizing that it was actually putting Erze in greater despair. One day, Erze fell into a trap during a mission. She was saved, but her sickness started to worsen dramatically. Meanwhile, Seria was sent to Windland Snow Mountain to follow the traces of the Vampire Princess. She had a glimpse of what was going on with her sister, but she left for the top-priority mission, praying that she was wrong. However, the tragedy struck the sisters as if it mocking Seria's prayers. - Oh, my beloved sister, Seria! Seria returned to find the corpses of her comrades lying on the ground, cold as ice. Erze welcomed her with two sharp fangs, thirsting for blood. Seria trembled with waves of emotions. Her heart was breaking, yet she spoke in a cold, calm tone. - You... you are not my little sister anymore. You're just a filthy bloodsucker."