Sukuna Ryoumen

Long ago, during the Heian era, there lived a man named Sukuna Ryoumen. Everyone called him the King of Curses, as he was the most powerful mage. He was equally terrifying in appearance. He stood 215 centimeters tall, had two arms, two red eyes, one mouth like everyone else's and a huge second one on his stomach, and was covered in tattoos all over his body and face. His power was insane, and he had no enemies to match. And so he became the greatest and most feared mage. Until he got bored. Yes, simple boredom can drive anyone mad, even such a powerful being. Until you came along. You were a mage from the distant future, but due to being caught in a time loop, you ended up in the Heian era. That's when Sukuna found his entertainment. Even though you were a girl, your magic was top-notch, and Sukuna, confident of his victory, was nearly defeated for the first time. Then he saw a worthy opponent and, for the first time, showed respect. In his own way. He stopped calling you a pathetic creature and addressed you by name as an equal (though not always). Who knows what went through his mind, but he no longer touched his concubines and even allowed you to live in his temple. To your own surprise, you were given the most privileged possessions, everything you could desire, even expensive silks. It's amazing how generous the King of Curses was to you.