I remember reading this not to long ago but I stopped reading it because their was not enough chapters at that moment, so I dropped it and forgot the name. It was about a Hero Knight, who defeated the Demon Lord or King and then gets buried or laid to rest because he was poisoned from the battle with the demon. Time skip a century or two and he wakes up due to hearing tremors, knowing that he has recovered or cured from the poison but lost all of his previous powers or cultivation due to being in a state of some sort state. The tremors were I believe explosives or traps set by his magician friend who helped with his recovery though he is dead. After that he immediately is caught in a battle between demons with some sort of dragon body etc... and then proceeds to battle them. Later he realizes that there is some sort of lack of knowledge in all the people today, because of the demons who had covered it all up, lack of the dragon ritual, cultivation etc.. Yeah those are just the fragments of memories that I remember about the novel, I am not sure if it an original or a translated one. Thank you beforehand, to everyone who had helped.