Great back story. Now no one can say that the MC didn't try. He tried to live a mediocre, normal, life once again...but he just couldn't. The MC is clearly destined for great things!
The odd thing is didn't he say he cares about his family and then a second later kills his half-sister?? It's weird...Wouldnt it be better to groom her into a useful pawn for marriages etc. If mc is evil and lustful enough when she's an ***** he could turn her into a loyal concubine etc...
Was it something I didn't understand or did he kill a five-year-old girl? If he wanted to start a new life, he could simply leave the family. He could just erase the memories of himself.