Osseth was born to an unknown mother and an unknown father, both of whom did not worship Ahunga. He was raised as an only child in the city of Romero, and grew up to become a bandit, committing many sins before The Divine Eclipse.
Before the end of the Divine Eclipse Osseth heard the word of Ahunga, and Ahunga spoke to him, telling him of a place where he can be rid of his sins. Osseth obeyed Ahunga and walked across the land through forests, prairies, deserts, rivers, and snowy mountains. Along the way he ran out of food and survived off the flesh of Hallows that would attack him.
He eventually reached a desolate landscape made entirely out of stone. It was there he climbed to the top of an active volcano and reached a sacrificial pit that overlooked the lava beneath it. He prayed to Ahunga as he walked to the edge of the pit and threw himself in the volcano when he finished, but he did not die, instead, his sins were burned off of the inside and outside his body, replacing the burned areas with dark blue scales.
Crawling out of the lava, he stood at the edge of the volcano in his renewed and purified form. It was then Ahunga renamed him Osseth and entitled him as the Burned One.
- Osseth's previous name is a mystery, however, it is known that his last name was Ferustorva.
- Osseth's childhood mainly involved playing with animals in the animal shelter next to the home he grew up in.
- After renewing his body, Osseth's appearance matched that of the Ahungan race, despite the blue scales covered all over his body.
- Osseth's face is the only part of his body that isn't covered in scales.
- The iris of his eyes are gold-colored.