I Have the Alchemy Emperor in My Head - Chapter 5

Lingyun, a fierce and savage cultivation genius takes over a dead teenager’s body. Coincidentally, they are both named Lingyun. Set in a alternate version of the 21st century, teenager Lingyun has been killed by someone with a grudge.

- Description from Novelupdates

“I'm going out to do something, so I can't take care of you any more. You can go down the mountain and have fun. But if you can't find someone who matches your Innate Pure Yang Body in three years, you're finished!”These were the last words the old man, who was Lionel Yeager's teacher, threw to him before he vanished. Meanwhile, having mastered most of his master's skills, Lionel Yeager went down the mountain and took his first step into civilization for the first time in years.With his unparalleled medical and martial arts, he sets forth on a journey, befriending new allies and crushing all the enemies that stand in his way, as he attempts to resolve his Pure Innate Yang Body constitution, and cultivate to the top of the world!

The boy named Ulysses has longed for the respected profession of priest since he was a child, and has been working hard for this ideal. However, by chance, he became the heir to the Demon King chosen by the “Book of Curses”. After experiencing many setbacks and blows, he is still working hard, trying hard, trying to return to the path of priesthood.

However, there are many powerful enemies in front of him.

Always getting lost, the heroic fiancee of Ulysses is single-minded, Rasha; guarding the “Book of Curses”, the little devil Aya who will do anything to turn him into a demon king; very worried and worried about his own children, the extreme north. Earth’s Ice Phoenix mother; Helen, the strongest weapon girl who can destroy the world for her father.

A witch with very bad magic but excellent swordsmanship, a saint with divine power, a dragon who burns like a flame, a Hydra who loves to mate and love everyone together… Today there are also many brave warriors who are ready to crusade against the Demon King.

In front of these lovely and enthusiastic warriors, can he really become a pure-hearted priest as he wishes?

(In this story of love and justice, the girls who can “tear down” the demon king are all brave)

- Description from novelbuddy

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.