The Reticent Blade - Chapter 72 - Strange Old Man

Calamity descends upon a a tranquil world in the black of night, transforming it into a death game! This a a true apocalypse, but this is not the end of humanity!

- 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.

I transmigrated as the hidden mastermind who betrays everyone at the story’s end.Since I wasn’t particularly interested in the destruction of the world, I was just leisurely waiting for the ending…“You are the only one who has ever seen my drawing of a boa constrictor properly.”“When I make plans to meet you at 4, my heart starts racing from 3… Is this what it means to be tamed?”For some reason, the heroines keep showing interest in me.