Was Sanemi Shinazugawa'S Death Avoidable In Demon Slayer?

Having an Awakenist as my wife meant enduring her monkish attitude toward sex. We could only be intimate on the sixteenth of every month. Every detail—my position, rhythm, even my expression—had to follow her rigid rules. If I showed too much pleasure, she would immediately rise and leave. We had been married for five years. Was I ever tired of this? Yes. Still, I always gave in. I accepted these limitations because I loved her. "The Saintess loves me too," I told myself. That faith shattered the day I was sent to extinguish a hotel fire. Amid the flames, I found my wife pressed close to a man in disheveled clothes. Between their arms was a young boy.

The moment I discover I'm pregnant, Courtney Smith, the leukemia patient I saved three years ago, turns up on my doorstep once again. She claims that her leukemia has relapsed again, so she wants me to abort my baby in order to save her life again. But I'm pregnant with my deceased police husband's baby. So, I tell her that I can only donate my bone marrow to her once I've given birth to my baby. After hearing my answer, not only do Courtney and her family not feel any gratitude toward me, but they also berate me for not helping them out till the end. "You can still have another baby once you lose this one! But if your pregnancy affects my illness in any way, will you be able to take responsibility over this?" Then, the Smiths abduct me to a shady hospital, where they forcibly put me through an abortion and remove my bone marrow. While their operation is a success, my baby and I end up dying on the surgical table. As they gaze at our corpses, the Smiths' faces are plastered with icy expressions. "Don't blame us for what we did. If you were the one with leukemia, we'd still make Court donate her bone marrow to you. One's life is determined by fate. If you can't survive, that just means you're fated to die." When I open my eyes again, I've returned to the timeframe three days before Courtney finds out about her leukemia relapse.

The Ivanovas and the Vitales are well-known aristocratic families who have maintained everlasting friendship through generations. My name is Anastasia Ivanova. I have been the daughter of the Ivanovas for twenty years, only to discover just now that I was switched at birth. When I was swept out of the Ivanova’s mansion like rubbish, Lorenzo, the youngest son of the Vitale family, firmly picked me up in spite of all objections. Lorenzo always acted cold and distant toward me. I didn’t know why he came to take me into his car at that time. He whispered in my ear again and again, ‌"I’ve wanted you for a long time."‌ He pinned me against the leather seat, making me cry until my voice was hoarse. At that moment, I finally understood his coldness over the years was not indifference but restraint. Soon after, Lorenzo overrode all objections to marry me. His parents were vehemently against me, but Lorenzo directly stripped them of power and became the youngest godfather. Scarlett Montgomery tried to stop us from getting married, but Lorenzo canceled all her credit cards and threatened to send her away. I thought we would have a happy life. Three days before our wedding ceremony, he planned to send me abroad, claiming enemies might retaliate. But, I accidentally overheard him talking to Scarlett in the hallway at night. "Thank goodness. You tricked her into leaving until after I give birth. You’re so good to me!"‌ He kissed her cheek, ‌"I don’t want Anastasia know our affair. You must keep it secret."‌ Their dialogue made me devastated. But I didn’t confront him immediately. Instead, I quietly completed my immigration paperwork as a way to make a clean break with him.

300 years ago, humankind created their own nightmare. Demons, are originally humans but the lust for power changed them inadequately, this is humans own doing. Around 300 years ago, a large asteroid bombarded the earth's very ground. This is the beginning of the birth of demons. This meteor was large, but out of the blue, a mysterious lifeform is intact in it's very core. A human named Cruzius Akiyoma was intrigued when witnessing these menacing looking creature. He interpret this as a blessing from heaven. He then owned the creature and conducted an experiment. He was surprised when he saw the structure and building blocks of life of this creature. He obsessedly pictured this as a one stepping stone through human evolution. He extracted the DNA of the creature and modified it in able to merged it to human DNA. Without any hesitation he then merged his DNA to the DNA of the creature. He is willing to offer his body to attain his goal, thus sacrificing his body is necessary. After the merging, he was surprised because nothing in particular happened. But, he suddenly felt a surging power circulating through his body. He screamed in pain as his body is gradually changing. Darkness fell upon humans as the scream of the first demon engulfed the sky, seas, forest, and fortress.

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.

When Mizuko slipped into the other world, she landed in the arms of a mischievous demon prince, Kenshi. New to the world, she didn't know he was a demon as he looked to her like he was a decent person. Because Kenshi helped her first, Mizuko decided to ask him for help in finding a way home while she fulfills the dead mage's request in relaying the message to the King. But no demon in Souzou helps unless they get something in exchange. A promise, it is what Kenshi wants the most.