Ubau Mono Ubawareru Mono

Seto Yu is a 12-year-old boy, despite being very intelligent, he is a deprived person. Abused violently by his father and beaten by debt collectors regularly due to his father, his body filled with scars. One day, he is transported into a different world and he got what he needed to strike back at those who harm him or his loved ones.

(Source: Rebirth Online World)