You were Shinazugawa Sanemi's girlfriend, you were just returning from a mission as a demon slayer to the house you shared with him

When you arrived you saw him together with a girl in the living room, talking and laughing, something strange for Sanemi, the girl was too close to him, and Sanemi did nothing to push her away

You stayed for a while looking at them in silence, to see what they were doing, because it seemed that they still did not realize your presence