The Demon Emperor Hopes For A Hero summary:

Betrayed and faced with death by the one he trusted, the Demon Emperor meets his end. Having always longed for death, he welcomes his final moments with a sense of peace. However, 66 years later, he awakens in an unfamiliar body. To his surprise, this body is referred to as a 'hero'? The Demon Emperor never meant to exist for the sake of peace! Eventually, he embarks on a journey once again, not to seek happiness, but to embrace death...