Mad King: Blood Reckoning

Abandoned as a fool, Kael was trained by the "Mad Demon" Vesa into an invincible warrior bearing the Sacred Dragon Bloodline. Returning home with his mother's ruby pendant, he saves his sister but is humiliated by his family. When the Frost Giant attacks, Kael saves them; his disciple kneels, revealing him as the shadow master. The pendant reunites him with his mother. But his treacherous senior disciple kidnaps his parents, forcing Kael to surrender his power. His father sacrifices himself. Grief-stricken, Kael awakens the Sacred Dragon Bloodline, slays both enemies with godlike power, and protects his family.