The return of the crazy hero

Since his childhood, and after he was appointed a hero, Dennis devoted his life to doing good, and helping the world eliminate the Demon King, until the day before he was to eliminate the Demon King, Dennis realized that his companions and all his loved ones wanted to kill him due to danger, and after eliminating them all, Dennis decided that he would do whatever he wanted and whenever he wanted, and leave the world in ruins, in this life and even the life after it. This novel is for those who love evil heroes, who are invincible, and merciless.