Bell's villainous friend

What if Bell had a childhood friend, the duo love each like brothers. But the two were destined to be enemies, the hero and villainous monster. Bell's friend knew his fate, but decided to change his fate with his own two hands.

Bell and his friend were almost Inseparable, almost... Bell was young and Naïve, his friend was different, Bell had a family, he grew up with love, joy and kindness. Where the other however had no one, his parents either dead or abandoned him, had to work, fight, steal just for food scraps, money, clothes, and beaten for look at someone or being different, nobody care about some dirty rat. He grew up with rage and hatred. And that lad dislike the gods, live among man and the they're way thinking and life. They decided to be adventurers, Bell did very little to train, his friend been fighting almost everyday of his life. Bell's friend decided to leave the village they were living in. He offered a Bell a chance to join him, but Bell refused and chose to stay. He wonders almost aimlessly around the country, continue to train, and to learn. Until he came across a stranger who offered a place with his legion. He joined his legion, he learned the truth, secrets and dark things long forgotten. Training in deadly long lost and forbidden tactics techniques and weapons that can kill devils, demons and gods. He find out he was a god's sacrifice. He grabbed a dagger and hide it. Right before he was sacrificed on the alter, he killed the cult leader with the dagger and summon a demon, Stoked a bargain with the demon to kill a god. He make a renegade army, which in turn influence others raise up and stand to fight, to hunt, to kill cruel and corrupt gods and their familias.

Some say he wants destruction, some say he wants chaos, he craves carnage or he's a dark hero