Well it says cultivation by destroying the country but he ended up by unifying the world so it's impossible for him and the others to come back to life until humanity's Datong country is destroyed and it's basically an empire cultivation game in disguise we don't know if he became immortal but we know that till the end he unified the world and was name the First Emperor which means we failed? They have to destroy it themselves in order for that to happen but with the way how everyone is that will almost never happen