Grind-to-Cash System: Buy SSS Skills to Spam them Infinitely with Cash - Chapter 16- Final Escape

A skilled but unfortunate modern-day assassin was killed in a freak accident. However, he soon found himself summoned to another world by an evil wizard, who had him possess the body of a boy as an experiment. After successfully planning the evil wizard’s downfall, he used the wizard’s body as a springboard to gain influence and power in his new world.

- Description from Novelupdates

Hyde arrives in a doomed world with nothing but his body and fragmented knowledge of the future from a game he once played. He has no grand ambition—why try to save a world already destined to fall? Survival is enough.That is, until he discovers his sister is also transported into that world.However, only he hears the Melody of Nightingale and receives the power to survive.[You have established a connection with The Forgotten Hollow.]Awakening as a Resonant—an elite group with supernatural abilities—he is thrust into a conflict between two worlds. Armed with the authority of space and time, he vows to protect his powerless sister at all cost, even if he has to fight against the Mirage creatures, other Resonants, or even Gods themselves.

After being awakened from their slumber, billions of people found themselves dispersed in various sealed crypts. Surrounded by earth, they each had only a shovel.

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.