MTL - Rebirth: National Crown Prince - Chapter 622 stubborn parents

There was once an immortal cultivator fighting for the fate of human beings. Unfortunately, he failed that time; but fortunately got another chance as he was reborn once more as a human, on the earth of 5,000 years ago. With a second chance, he not only would embark on the road of saving all mankind, but also would retrieve his human nature on the new journey that would last for 5,000 years.

- Description from Novelupdates

This is a therapeutic romance novel that mixes psychology and science fiction.

As a wandering soul trapped in endless cycles of reincarnations, Claus must decide what to do in his current life.

An Individual from Earth finds themselves in the Shinobi World, equipped with a Scientific System. From that moment, he delved into scientific research far ahead of its time.