If I Don't Die, You Will

Reborn into another world as a fetus, Xu Que has lived cautiously for eighteen years. Just as he earns a spot at the Immortal Academy, his father orders him to give it up for his younger brother. This spot is crucial to his future, and as he struggles to decide, a system appears, giving him confidence. He cuts off his bones to return to his father and his flesh to return to his mother, severing all ties with the Xu family. Kill! — Description from novelcodex.org