Why Do Demon Cultivators Insist on Forcing Me to Become a Demon?

My intention is to cultivate immortality, But the world is broken, Only the devil is at ease, Why bother to cultivate immortality? The story tells: events in three eras, couples in the first era, brothers born in heaven and earth in the second era, brothers in the third era... Main plot mystery: Why was Tiannan Continent originally called Tianxiao Continent! What happened to the first generation of skeletons? Why! These are all things that are about to come to an end. I am writing this here to prevent myself from forgetting.