Nanomancer Reborn - I've Become A Snow Girl? - Chapter 24 - Shadow Temple p3

A nordic romance that burns up coldly!

Ethan Cross was a politician serving as the Secretary of the Department of Energy in the United States of America. He was also an engineer and a scientist prior to his position, to which he was hailed as a “King of Technology” as he was able to invent revolutionary technologies one after the other.But his life was cut short when the vehicle he was in was rammed by a truck from the side, and immediately after, he awakened in the body of a royal prince, Bruno de Elysea, who was a complete opposite of Ethan in terms of knowledge and capability.One thing he noticed is that in this new world, everything was so backward. Technology and politics. He desired to change them but by doing so, caught the eyes of those who opposed it.

A teenager named Evan Mason was reincarnated into the magical world of Harry Potter and goes to school at Hogwarts!
With only his knowledge of the future and great talent for magic, he takes the path towards the top of the magic world, only to realize that ever step he took, changed everything!

- Description from Novelupdates

Dr Dalton Wyatt, a world renowned Scientist and Inventor is transmigrated to the body of a high school student Dalton Wyatt who committed suicide due to unfortunate circumstances and complicated life.