How Did Rui'S Sister Die In Demon Slayer?

I picked up a system with my sister. The system said only one of us could bind to it, and the other could take twenty million dollars. My sister shoved me aside and chose the money. Ten years later, she squandered everything and ended up homeless. Relying on the luck the system gave me, I excelled in my studies, climbed the career ladder, and reached the peak of my life. Driven by jealousy, my sister stabbed me to death at my birthday party. When I opened my eyes again, I was back to the day we found the system. This time, she said without hesitation, “Luck is too intangible. I’ll take the loss. You can have the fortune.” I knew she had been reborn, too. What she didn’t know was that the luck granted by the system always came at the cost of one’s lifespan.

My older sister was always kind-hearted, while I was born a natural troublemaker. When the intense heatwave struck, our family stocked up on supplies and stayed indoors. My sister saw a little boy, who seemed about seven or eight years old, crying and asking for help. She decided to take him in. “We’ve plenty of supplies anyway. One more person won’t make much difference. Besides, he’s just a child.” I warned her that the boy looked oddly mature and might not be as innocent as he seemed. I suggested we observe him a bit longer. She said I was a cold-hearted troublemaker by nature. Then, she went and let him in anyway. Not just that, but she also convinced our mother to force me to share a room with the boy. That night, the scheming “little boy” secretly climbed into my bed. I was brutally assaulted. Yet my sister told me to let bygones be bygones and marry him. To force me to obey, she locked me out on the balcony at over 140 °F. Enraged, I set a fire and killed everyone. When I opened my eyes again and saw my sister safe and unharmed, I smiled. This time, I would show them what a troublemaker really was.

When my sister, Danielle Campbell, and I are born, our parents hire an astrologer to read our futures. The astrologer says Danielle will develop severe depression because of my success. After the SAT scores are released, she'll jump from the roof of our school and end her life. To save Danielle, my parents spend 18 years tearing me down. On the day of the SAT, they even confiscate my exam permit. I fall to my knees and beg them, slamming my forehead against the tile floor over and over. Dad kicks me into the walk-in freezer and locks the door from the outside. "You know your sister will die because of you, and you still insist on taking the exam? Are you trying to drive her to her death?" The freezer is set to -22 degrees Fahrenheit. I'm wearing nothing but my short-sleeved school uniform. I pound desperately on the door. "Mom! It's so cold in here! Please let me out!" "Oh, stop pretending." Mom's voice is sharp and cutting. "The refrigeration isn't even turned on! Danielle is only one step away from escaping that prophecy, and all you can think about is yourself?" Their footsteps fade into the distance. Blood keeps streaming from the wound on my forehead, soaking into my uniform before turning ice-cold. I curl up in the corner. Little by little, my body grows stiff.

My sister Iris almost died from anemia. The day she was hospitalized, my whole family started blaming me. I'd been frail since birth, so Mom and Dad had always poured all their attention into me. The new school supplies were mine, the new clothes were mine, and even on the birthdays we shared, the cream and chocolate part of the cake always went to me first. I used to hear Iris crying at night. But whenever I tried to comfort her, she just shoved me away. On my twelfth birthday, I came home from school with a perfect score on my test, beaming as I pushed the door open. Mom and Dad's eyes were red, and they looked at me as if I'd done something terrible. “Why can't you ever be nicer to Iris? We give you everything, and you should be thinking about her too.” “The doctor said her health problems are all because of how she feels.” “You're so spoiled, so selfish.” I lowered my head. They didn't know that I was frail because I'd made a deal to take Iris's death for her. Tomorrow, I was going to be erased.

I died beneath the Ferris wheel. The killer took a photo of the Ferris wheel and sent it to my mother. 'Mom, I want to ride the Ferris wheel with you too,' wrote the killer. In my mother's voice message, her tone was filled with hatred as she replied, "How dare you ask to ride the Ferris wheel with me when you killed your own sister? Why won't you just die?!" As she wished, I was dead. However, what she didn't know was that the one who killed me was my so-called dead sister.

Serra is a normal senior high school student who works really hard every night and weekend to pay off her parents' debts from loan sharks. But when she couldn't keep up with payments anymore, she decided to end her life. Surprisingly, she woke up in a different light-- in another world. What's more shocking was when she is addressed by one of the people as the demon king's bride.