Heretical Fishing - Chapter 8Book 5: : Mark

When a person dies, they either die light as a feather (aka unimportant) or heavy as Mt. Tai (aka very important).

Ethan Carter was nothing special—an average man living an average life. No great ambitions, no dreams, no love, just existing.Until a truck ended it all.But death wasn't the end for him. Waking in a peaceful void, he met Rob, a cosmic being with a twisted sense of humor. Instead of allowing Ethan to pass on, Rob gifted him an overpowered divine elixir—the Enhanced Fountain of Youth – The Divine Spring.Follow his jouney in the multiverse.--------Note: MC makes mistakes at first and learns from them later.

As a man who had lived for 20 something years and had always considered himself as a straight man, he woke up one day and found himself possessed by a stupid and cute system. Moreover, it was a gong-shou cultivating system?! Let’s see how a shou with raised hackles evolves into a (pseudo)queen shou, incidentally with a story of a hidden loyal dog gong.

- Description from Novelupdates

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.