Use Technology to Dominate Attack on Titan

In this world, giants are the most terrifying things, but humans are not afraid of the development of technology. This is actually a human being. The protagonist traveled into this world and defeated the entire world with technology, bringing business to the owner. Can he defeat the entire world, protect this tribe, or make peace with the entire world? This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.