Memoir of a Demon King

In 2025, the System appeared on Earth, and with it, magic, aura, monsters, and portals to other worlds. In 2030, a prophecy was given about the impending arrival of a Demon King. The strongest from every nation in the world banded together and waited at the portal where the Demon King was supposed to emerge, but they never came. The portal simply closed without event, and the whole world was left perplexed. A few with sharper eyes claim to have seen a woman's silhouette in the center of the portal for a split second, but with no actual evidence, the claims were dismissed as a hoax.   23 years later, when most had forgotten about the incident entirely, the truth was finally made known, and surprisingly, it the Demon King herself who announced it. Lucille Montague, who was previously thought to be merely a piano professor with an intriguing background, revealed that she was, in fact, the Demon King, and that it was her who had emerged from the portal on that fateful day. The reveal came in the form of a memoir detailing her version of the story of how she came to be a Demon King and what she intends to do with her power.   With no way to verify anything other than the fact that Lucille is as strong as she claims to be, the world has no choice but to believe what she wrote, but can her words be trusted? Is her story really the truth, or is it only what she wants the world to believe is the truth? Is she really as peaceful and benevolent as she claims to be, or does she have something to hide?   Edit: Due to recent policy changes, I have updated the tags to only Disturbing Content, because there will be some of that. Profanity and violence will be there, but not in large enough quantities to necessitate the warning tags. There will be no sex scenes. There will be some potentially disturbing content (slavery, mental illness, mentions of rape, etc...) so I'm leaving that tag in though.    This story is a rewrite of my story, Pride, Greatest of the Sins, which can also be found on Royal Road. In the original draft, I started it with 0 plans, and no idea where the story was going, so the early chapters were aimless and the later chapters suffered for it. You can go read it if you'd like, but it is unfinished, and it does contain spoilers for this story, so if you prefer an untainted reading experience, I'd advise against it. This version is more cohesive, and I actually already know how the story will end this time, so I will make fewer mistakes in the early chapters.