In 1993, a 23 year-old Kaitlyn Byun had moved back to America after living in South Korea for 15 years of her life. Being gone from the US way of life from the age of 8, Kaitlyn grew up to respect her parents and do nothing to shame them. That's why Prometheus had so much trouble convincing her to do the deed with him one night. At first, Kaitlyn denied, but after a few drinks and some sweet talk from the god, Oswald was concieved. Although her father disliked the fact Kaitlyn had done this and was disowned her, her mother remained true and supportive of her daughter, and on the 30th November 1994, Kaitlyn gave birth to a baby boy who she named Oswald.
Kaitlyn always secretly blamed Oswald for her father disowning her, which is why, when she got married to man named David, she distanced herself from Oswald more and more as the years went on. Little did she know, David was a son of Mnemosyne and had found out that Oswald was a demigod too through a dream Mnemosyne had sent him, pitying the ignored child. David attempted to talk to Kaitlyn about the heritage and that it meant nothing really, and how Oswald was still the same Oswald he had been back when he was younger. However, Kaitlyn saw this as Oswald being a freak and left the two upon David's confession that he too was like Oswald. Due to not wanting her pride to be hurt, Kaitlyn fought for custody over Oswald, in which she lost and moved back to South Korea to avoid any further embarrassment.
David and Oswald grew up very much so like a true family, a very different lifestyle to when Kaitlyn was around. David was always ready for Oswald's first attack and promised to himself, as well as Oswald and Mnemosyne that he'd protect the younger demigod. Because of this promise, David was strict on times concerning Oswald being alone or not with him, much to Oswald's displeasure. At the age of 13, Oswald and David were playing catch in the back garden when a hellhound came from behind the treeline that bordered their garden from the woods. David, having been at Camp, killed the monster with ease. Curious, Oswald asked David what it was. David then told him about the Greek world, the world he belonged to. He tried to suggest the topic of going to Camp to train as a demigod, yet Oswald refused to be split up from David. This carried on for quite a few of the attacks Oswald would experience - David would help him out, suggest the topic of Camp, and Oswald would refuse. Every time.
When Oswald was 18, the final attack he'd face with David occurred. Although he had been trained by David to some extent, Oswald was still fairly weak when it came to monsters. On one of the final nights of his senior year, Oswald partied with some friends until the early hours of the morning. He returned home to an empty home. The fact that David wasn't there didn't phase him until the next morning when he tried to search for his father. Searching around the house, Oswald found no trace of David until he reached the basement. There, David's dead body was in the centre of the basement, and in the darkest corner, a hellhound watched Oswald's evey movement, waiting for the right moment to strike. From what Oswald could make out, the monster had some scars varying from bad to nothing too bad. Beside David's body there was a note. This note held Oswald's interest and he inched slowly towards it, aware of the monster watching him. As he was about to pick up the note, the hellhound attacked leaving Oswald completely off guard.
Frantically searching for a weapon, Oswald picked up David's pencil that he kept in his back pocket, knowing it was his celestial bronze sword. Gripping the sword tightly, Oswald swung around, praying to slay the beast. After a few failed attempts a hiss sounded around the room, and in the place of the once dark beast, was a pile of gold sand. Shocked by what had happened, Oswald's mind strayed far from his original goal of reading the note. After a while of breathing in and out, he inspected the note, paying attention to each little word. The note explained that no matter what he does, he must go to Camp. Seeing as his father was dead, Oswald complied with the note and packed a few clothes, some supplies and drove to Camp.
On the car journey, the death of David really sunk in to Oswald's mind, causing him to grieve. Hades saw this and smiled, ultimately. You see, Hades had an annoyance with children of Mnemosyne, ever since one of Mnemosyne's most favourite children, Jayson Steele had managed to complete the tough, almost impossible, tasks he had. From then on, Hades had a certain grudge towards children of the titaness, especially her favourite kids. It so happened that David had held a place in Mnemosyne's heart due to the kindness he showed to those he met and the loyalty to Oswald. Seeing as Oswald was due another attack soon - well, in his opinion - Hades sent the hellhound to kill David, and then maybe Oswald. The grieving son of Prometheus only helped Hades forge a trick.
One night, long after the death of David, in which Oswald still grieved about, causing him to rarely leave his room in his Cabin, Hades appeared to the demigod in a dream with the offer of seeing David for a final time. Of course, Oswald agreed without thinking through his actions. Hades explained that throughout the US there were places where pieces of the first fire that Prometheus had given to mankind rested. The ordeal was simple. If Oswald managed to get a piece of the fire, he and David would be reunited for a final time. To Oswald, this deal meant the world to him, and he packed up and sneaked away from Camp to complete his own personal mission. However, Hades had made up the places by looking on a map of the US and picking out names of places and states that interested him. He sat back, waiting for the demigod to fail and be even more stricken with the loss of David.
In Nevada, Oswald searched for this place Hades had talked about - a building that appeared to be a shack, run down by the weather. After searcing for many days he came across a small building that matched Hades' description almost perfectly - coppery colour, rundown, looks out of place. Excited, Oswald wandered in to find that he was in an abandoned forge of Hephaestus. With excitement taking him over, Oswald looked in every place he could find, until he found a large box. Inside, a single note with the words 'Prometheus' Fire - Only use for Olympian weapon making' on it. Below that, a small case with a medium sized flame flickered. He stole the fire and began to make his journey to Hades.
In his home state, rather, the road in the woods behind his old house, Oswald stopped to get some sleep. By this time, news had gotten to the gods that a child of Prometheus had done what their father had done centuries ago. Zeus, accompanied by Hephaestus and Mnemosyne, went down to get the flame for themselves. Upon waking and seeing the three gods, Oswald panicked and ran deeper into the forest. Hades, annoyed that the child managed to find a flame he made up the location of, sent his furies on the demigod, who killed him without a second thought. Nemesis overlooked the death of Oswald and found it unfair. So, she revived him as a revenge spirit, giving him immortality, and the motive to get revenge on Hades, or his children out of pain.
Now, he resides at Camp, bitter over the whole thing, waiting to carry out his plan of revenge.
Oswald Byun 
