Hey, amateur author SevenSeven here. Please check out my book, The Demon's Solace
To put the synopsis in short, it is about the former "Demon King" and his journey for revenge toward the Devil himself. He who lived 276 lifetimes versus quite literally the epitome of evil, a pawn's rise to defeat the mastermind behind it all. A dark tale of tragedy, action, and magic, featuring an antagonistic main character.