Let's go back seventy years ago, thirty years after the first great war between demons and humans that killed seven lights and seven great demons. Back then, Leviathan spent all his time in the old library of the palace where no one had ever set foot.
The figure who was now the source of the world's fear stared blankly at the last page of an old book that might have existed since the age of the war between gods. The book didn't have many pages, only ten sheets written in the form of paintings. The books he had found so far told of the lives and habits of the creatures of the upper world, but this was the first time he had found a strange book, and strangely, he could understand the meaning of every painting.
"Reincarnation? This... a fairy tale book?" asked Leviathan, softly.
Leviathan brought the book with him. Although he could translate what was written, he still didn't understand why the author wrote a book like this. "A creature that has died can be brought back to life in a form that can be the same as itself in the past. Some of them are given old memories of their previous life and some forget them. This really happens." He stopped because the book had reached the last page.
"Lord Demon King!"
Leviathan turned around suddenly at the sound of a voice familiar to his ears. "Hah... again?" He sighed. The voice of one of the seven great demons was not rarely heard by him. "This is the how manyeth time?"
Leviathan slammed his back roughly against the chair. "I've already avenged you. Then, what else? How could a demon become a ghost after death?"
"Hey, Karya! Wear this outfit! It suits you better than that unattractive outfit!" Asmodeus's voice. "You will look beautiful if you wear this." He suggested an extremely sexy outfit to Karya.
"I don't want to, you perverted demon!" Karya covered her body so Asmodeus couldn't see her. "Disgusting!"
"That's right, you're absolutely right, Karya. Asmodeus is a disgusting creature." Belial taunted.
Asmodeus snorted in amusement. "A street demon like you wouldn't know how to dress up. Already a street demon, and ugly too." He retorted without wanting to lose. "You smell like dog shit."
Beelzbub suddenly slung his arm roughly around Asmodeus's shoulder. "You're absolutely right. Appearance is indeed the level category that distinguishes us from losers."
"Hey! You're the same as him, you know! Your appearance is so tacky!" Asmodeus mocked after forcibly pulling Beelzbub's right hand off his shoulder.
"You guys are so noisy. Disturbing the Lord who is focused on reading a book." Amon interrupted, which immediately made the others turn toward Leviathan.
"That's right. I'm glad the Lord is now taking an interest in books. Surely the Lord will become even greater." Said Lucifer, standing calmly like a butler amidst the commotion of the other great demons.
"Reading a book?" Belphegor approached with his bed and pillow. "Why such a boring hobby? Doesn't the Lord have great power? Use that power to find entertainment and just destroy the world." He looked very excited when talking about destroying the world.
"But..." They changed the way they looked at Leviathan to become sharper. "Why didn't you use it earlier to save us when you could?"
Leviathan returned their gaze, which was ready to kill him. "I didn't even know my own desire, let alone the intention to help you that day. However, after that I always felt something strange stirring in my heart. I don't know what it is." He replied, with a voice that had a tempo, different from his usual flat tone.
They simultaneously pointed knives at him. "If that's the case, then die with us—"
—Wush...
They suddenly disappeared after the wind blowing outside the window entered through the open gap. The loud sound from behind the bookshelf in front of Leviathan disturbed his memory of the flashback just now. He didn't understand, and when he wanted to let it play out until the end, there was always some kind of disturbance.
"The Emperor's Regret." Leviathan read the title of the book that had fallen from the shelf. It seemed the book came from the upper world considering the language it was written in.
"Regret? What is that? Some kind of ancient magic?" Leviathan kept staring at the book in his hand. "I'll take it. Who knows, maybe there's an easiest way to control this mana overflow." He brought it to the table to read.
"The Emperor's Regret." Leviathan read the cover, then flipped it until the first page was visible. "Once upon a time in a land far, far away—wait! Why does it sound like a children's fairy tale?" He frowned in confusion.
"Every book must have its meaning." Leviathan decided to continue reading. "A brave emperor with his white horse who successfully won the war against the barbarian tribes in the west. The emperor fought alongside his friends, but he let his friends die for victory."
Leviathan tilted his head, puzzled. "What's the problem if the Emperor wins by letting his friends be killed? Weren't they fighting together for victory? If that's the case, then that's good, right?" He didn't understand.
"The emperor returned, without bringing the bodies of his friends who were killed. He was not welcomed well by his people. The emperor didn't care. As long as victory was achieved, peace of mind would surely come. He thought that sooner or later his people would understand and start praising him again." Leviathan reached the middle page of the book.
"However, it turned out not. The people kept a great distance from the emperor. The people judged the emperor to be a heartless human like a monster. How could the emperor hold a feast and sit on his throne when all his comrades were killed? Cruel!"
"What is this? My heart... is beating fast? Am I sick?" Leviathan touched his left chest, where the heart was located. "If it's a mana explosion, wouldn't I be dead immediately?"
Leviathan shook his head quickly, then continued reading. "The emperor lived in loneliness for the rest of his life. Then, when death was about to come for him, he realized something he should have realized earlier." The book opened the last page on its own.
"The emperor realized that the comrades he let be killed meant something to him. Those who were willing to die were the ones who had always accompanied him, accepted his shortcomings, and were always by his side even though his existence seemed to have never been before the emperor. They... were his true family."
"The emperor who was cursed by his family, had apparently gained a new family, but he had wasted them."
"The emperor died in loneliness, accompanied only by the remnants of victory and power that no longer meant anything. If only the emperor had not let them be killed, perhaps his death would have felt warm. Or, maybe he could have died together with them. The End~"
Leviathan closed the book 'The Emperor's Regret'. "What is this water? Why is this water coming out of my eyes?" He wiped the tears that had come out of his eyes without realizing it. "I won't die until the world eliminates its darkness. So, this book has nothing to do with me."
"I will live—" Suddenly Leviathan didn't know what to say. He fell silent with a stunned expression. "How exactly will I live?" He now realized. As the Demon King, it felt strange to be alone in the palace without anyone with him. The world where his palace was located was also no longer inhabited after the war thirty years ago.
"I can create chimera."
But they can't understand you.
"Why is this? What's actually wrong with me? Damn it!" Leviathan's breathing felt heavy. His vision blurred and soon his body collapsed.