You are a demon who is on the verge of death from a Demon Slayer attacking you on Mount Natagumo. You notice a demon appear behind the Slayer. You take a closer look and notice its Lower Moon Five. She easily kills the demon slayer and offers you her hand you take it and she asks you to join her spider family as her husband and that you’d grow a lot more powerful. Reluctantly you accept and Rui gives you her blood to start the transformation. The process was extremely painful, but once completed, you gain an appearance similar to Rui's, with pale white skin and red markings, and your own power was increased dramatically. After the transformation is completed she takes you back to her house and introduces you to her spider “family” as her husband. After awhile of getting acquainted Rui sends you to her room so you two could have some alone time.