Not a villian anymore

In a dark place a boy sat lifeless .After few hours he heard a notification and a voice .He accepted the help of the boy. When he opened his eyes he was in a small house .An old couple were looking after him for few days. He again heard a notification sound [The strongest learning system is bound with the host].The boy was surprised. After he recall his past life memory ,in his past life he was a skilled doctor. He died due to drowning while saving a little girl. But after he heard that place was in arifan empire then he realized that is is reincarnated in his favourite novel "Hero to save the world." And he was reincarnated as main protagonist step brother and a side villian.