Cultivation? but I Will Only Be Resurrected!

When I woke up, I became an "exceptional figure from heaven" in the world of immortals. Without spiritual roots, it is impossible to cultivate immortality, but it comes with immortality and instant healing BUFF. I was hunted down and studied by various major sects, and I tried cutting it into pieces and putting it in a pot. Unfortunately, I couldn't die and always came back to life. Until that day, the Demon Lord pinched my chin and sneered: "You don't know how to practice? It just so happens that I need a living toy that will never wear out." I smiled and put the dagger into her chest with my backhand: "What a coincidence, this is what I was waiting for -"