He was not powerful, he was not super strong and he had no abilities... he had not been conceived out of love from both his parents. HIs father had wanted a demigod son who was powerful, his mother wanted a child and she was all that loved him but he was content with his position no matter how his father may be disappointed with him he was not upset. See when his parents had tried to conceive he was going to die, his father went to the fates and begged them to save their child in hopes he'd still get a powerful son and the fates listened but left out the part where they would take away his powers as a son of a god. Granted it kept his mom from having to do anything she didn't want to so as to protect him, no matter his position he knew everything he could about modern mythological areas after all he had the sight.
He had helped demigods before when he was 12 he gave money to some to get back home, at 13 he had saved some others from a shipwreck whilst on a cruise and when he was 14 he had nearly been killed by a jet black haired girl. (AN: Since he has the sight and he is the son of a god he still can be hurt by mythological and regular weapons.) He had refused to answer why he had nearly been killed but did elaborate he had the sight, he'd helped her get her friends out of the museum. At 15 he had been training as a military soldier with his step-father Jacob who was a Navy Seal, he also had the sight and he knew of Percy's circumstances but still treated him as a son. When he was 16 the battle for Manhatten happened and he along with Jacob had defended some retreating demigods with a shotgun loaded with celestial bronze bullets and a sword, this is where the story begins or at least it does.
Upon Olympus after the battle, he had been escorted up by demigods and now stood before the Olympians, Zeus looked down at the boy no older than his own daughter and spoke softly but his curiosity easily telling why he had summoned Percy there. "Why have you helped us, child." Percy simply looks at Zeus. "My father, well actually my dad is back down there but I digress... my biological father is a God, I was to die as a child and he went to the Fates for help they saved me but did not allow for my powers so I was useless to him... I do not love the man that is my biological father by the enhanced reflexes and so on is useful." Zeus automatically understands and glowers who'd dare treat their child like he and his siblings had been treated by Kronos, his anger is barely in control as he seems to realize that this boy was his nephew. Turning to Poseidon he speaks coldly but loud enough for all to hear. "You tried to conceive a child with a mortal for power and when it did not work you through him aside." Poseidon sat frozen in his chair as everyone looked at him in disgust, surprise, and anger.
Percy gave none of his emotions away as Zeus spoke to Poseidon and the others evaluated him, finally, Artemis spoke. "You are obviously skilled, but I'd like to know who taught you to take down a cyclops my hunters could not take down." She spoke not with anger but surprise she was intrigued by the boy, he looked at her and smiled softly. "My step-father was a Navy Seal of the United States military and has the sight along with my mother, from a young age I was taught to defend and attack along with tactics and battle strategies by this man." She accepted the answer and looked at the others waiting for Zeus to speak to Percy again when he did he was no longer angry but also intrigued. "I will try to get your birthright given back." And when the Fates came and he asked them if it was possible they simply smiled their forms surprisingly around 20-26. "The boy may have no control over the sea and water but we gave him an ability to that none have had... those he kills will forfeit their abilities to him so that cyclops he killed no longer has it's immense strength." All looked wide-eyed but happy with the outcome they were not stupid or idiotic as they once were, this boy would not willingly attack anybody unless those he loved were threatened.
He left to return to his family and explained everything to them, the next time he would be seen was when he was twenty-four and it was whilst defending some kids from some hellhounds, he had been summoned to Olympus yet again but this time they seemed very confused. "It has been eight years Perseus... it is obvious by your clothes you are a soldier and I thank you for defending those demigods but you should not be apart of this world at this time." Percy chuckled. "With all due respect sir I was apart of this world the moment I was born, and I know why you don't want me in this I know of Gaia's return and the war but that won't stop me." Zeus sighed to himself and others chuckled having expected this. Aphrodite made a move and Percy simply raised an eyebrow saying. "Is this all you have, cute mirages of what I see in an ideal woman and allure." He scoffed slightly and turned back to Zeus as many of the other goddesses smiled slightly happy to see Aphrodite finally not have control over someone.
As the war went on Percy helped as best he could before fading back into the background as it ended, he was no hero he was just another soldier who fought for innocent people and would be there when needed.
He eventually married and had two sons named Marius and Raven, they mattered most and he lived happily with his wife, sons, and parents... maybe he didn't get to be a hero and maybe he didn't get to have his biological father but he couldn't bring himself to care about what if's.