What Fan Theories Explain Demon Slayer Pillars Deaths?

It was in the Era of Harmony, trillions of years ago, when Chaos first arrived. To stop all existence from growing rampantly and exhausting all sustenance, the Creator of the universe took on Chaos as its body, the void as its vigor, and black holes as its jaw—a combination to create a world-ending coffin, devouring the seas and setting lands aflame, reducing all to ashes! Later, millions of years ago, the gods waged wars against each other when the same coffin appeared out of nowhere, massacring their ranks and decimating the divine realm. Since then, it had gone missing, but its name continued to echo throughout the universe, leaving both gods and demons in fear! Millions of years later, a youth was buried alive and fused with the coffin where he was kept, and he became an undertaker whose name was heard throughout all worlds. "I'm really bad at saving lives, but I'm quite good with ending them," he said quietly with a cool visage. "I possess the Coffin of the Gods, and I can send anything and anyone to their deaths: humans, worlds… or even the gods themselves!"

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.

Kiara was the Demon Queen And was ruling the Demon world, but suddenly an angel came to her world. He made emotionless Kiara believe in true love and then killed her brutally. However Kiara wanted her revenge. She was so desperate that her soul travelled in the time space, instead of dying. On the other hand after Kiara's death demon world destroyed, and Kiara's Crown which can give powers beyond their imagination fall in portal which connect all world together, That's why all the demons started searching for the crown. 10 thousands years later, (Human world) In hospital a girl with extraordinary facial features declared dead , but suddenly the girl opens her eyes and says "Prepare for destruction! DEMON QUEEN IS BACK. This time WHOLE UNIVERSE WILL SUFFER MY RAGE!"

My family has always considered me a harbinger of misfortune. It's all because I can see a countdown to my relatives' deaths. I tell them when my grandfather, father, and mother will die. It all comes true due to various accidents. My three brothers hate me to the core because they think I cursed my parents and grandfather. My mother actually dies after giving birth to my younger sister, but my brothers dote on her to no end. They say she's their lucky star because everything goes well for the family after she's born. But didn't Mom die while giving birth to her? On my 18th birthday, I see my death countdown when I look at myself in the mirror. I buy an urn I like and prepare a meal. I want to have one last meal with my brothers, but none of them show up even when the timer hits zero…

He died killing the Demon King. He woke up sixty years too early. Now the monster is a young man. And he is running out of reasons to stay away. --- Lysan Dusk was the hero who saved humanity. He killed the Demon King, ended the war, and delivered the world from suffering, and his reward was betrayal. He wakes up in a young student's body in a dormitory room of a magical academy, and the calender shows that the date sixty years before he was born. The world outside hasn't broken yet. The war hasn't happened. Lysan's plan is to keep it that way by staying completely out of it. Fail his combat exams, spend whatever borrowed time he has left, living a quiet life, where nothing requires him to be a hero. The man who will become the Demon King, the most feared monster in history is still young and beautiful, with pale grey eyes that find Lysan across every crowded room like he is the only person worth seeing. Lysan knows what those eyes will become. He has looked into them across battlefields, spent a lifetime seeing them in nightmares. He never expected it to feel like this up close. Roman is everything Lysan was warned about — magnetic, dangerous, impossible to ignore. Everyone except Lysan, refuses to be charmed, refuses to feel anything at all. But now, he is failing spectacularly at them because Roman keeps finding him. Keeps watching him and making Lysan's carefully rebuilt walls feel like paper. Lysan knows the ending. But for the first time in two lifetimes, he is wondering if the ending can change. If the monster can be loved instead of killed. If staying is braver than running.

Lyon Aschere, well-known as "The Reaper" is the youngest person to be an official Royal Knight of Avaritia and is also the personal Knight of King Charles Avaritia II eldest daughter Princess Jiniya Avaritia. But with him being a lowly commoner with high aptitude for magic and martial arts his status as a Royal Knight was hidden from the public. A few weeks after being appointed as a royal knight his left eye began to ache, showing him disturbing images, thinking that it was only a matter of hallucinations he disregarded it. Until the Princess found out about his problem, the princess being kind to her childhood friend, decides to help him figure out what is happening to his eye, venturing out to different Kingdoms looking for answers. But to their surprise the world was riddled with secrets that dated back from thousands of years. The story follows Lyon and Jiniya as they try to understand what powers lie behind Lyon's eye.