Hyper Intelligence with a System HIS

Ethan was a military scientist from Earth who, after taking his own life, was reincarnated into a new world in the body of a child, however the skill he gained while on Earth followed him like a curse from his past. In addition, his body gained a new ability called "System" that began to coexist with his Hyper Intelligence.
Despite having fearsome abilities that could take him to the top of the world, Ethan wasn't aiming for anything like that. He was already tired of the military life, the deaths, the wars, the conflicts... All Ethan wanted in his second life was peace.
Even so, fate didn't seem to have the same plans as him. Faced with the rottenness of that new world, Ethan decided to crush anyone who threatened the lives of the people he loved.
“Everything will be different this time! I will be free, and if this world gets in my way... I WILL CRUSH IT!”