not really good with book names sorry

There was once a Legendary monster who was outcast unjustly for being too powerful. They tried to kill him at birth but failed and he escaped. His father saved him and took him away. His father betrayed him and tried to control him because he thought that he was crazy. They were told to kill and did what they were told. He was raised to become a monster and none could stop him he was number #1 He had been born in the era of physical might and as a result of his physical stats being as high as they were from birth he was basically invincible even if someone had managed to hit him with a Dragon crafted weapon there would be no damage his physical might at birth was just too great and weapons had zero affect on him even the strongest warrior paled in comparrison and even with the strongest weapon even they would fail to inflict any damage upon him. This was his birth stats and each and every single one of these physical stats were at that level. When they tried to kill him they did so using posion it was the only real method. He had a unique abillity as well it was the abillity to steal the power of any defeated enemy and add it to his own. As a result every battle made him stronger. However at the age of 6 years old they were introduced to magic. The very first Demon Lord had been born and to rival it humanity had been blessed with magic and the Hero summoning. The Demon Lord paled in comparison to the monster. However even after using his unique abillity the monster was never really able to use magic but instead that magical power enhanced them in magical resistences.