Son of the necessary evil

The youngest child of the heavenly demon, ma shin-woo was always bullied by his siblings and even low grade servants for being an illegitimate child, his mother was a maid who was executed after his birth. he lived his whole life trying to survive countless assassination attempts, and finally one of them succeeded... on the verge of death the cries of his broken soul were heard and the divine blessings of the god came to him... now his only goal is to become the strongest and take revenge on those who did him wrong