A great plot could involve Percy being wrongly accused by the Ares kids of stealing something important from their cabin. He then has to prove his innocence while also dealing with the fact that the real thief is trying to frame him to start a war between the cabins. Also, Percy could be forced to train under the Ares kids' brutal regime, and in the process, he learns some new combat skills and a different way of thinking about battle. It could lead to him growing as a hero in unexpected ways.
One plot idea could be Percy having to team up with the children of Ares for a special quest. Maybe there's a powerful ancient weapon that only the combined strength of Poseidon's and Ares' descendants can wield. Another idea is Percy getting caught in the middle of a feud between the Ares cabin and another cabin, and he has to find a way to make peace. Or perhaps Percy discovers he has some unexpected connection to Ares' lineage that changes his perception of himself and his powers.
One idea could be Percy struggling with the duality of his parents' natures. Ares' aggression and Aphrodite's love and beauty aspects could be at odds within him. For example, he might be in a situation where his natural inclination towards love and peace from Aphrodite clashes with the need for battle and aggression from Ares during a war between the camps. Another plot could involve Percy having unique powers due to his dual heritage. Maybe he can use love as a weapon in a way, like making enemies fall in love with each other and thus incapacitating them, which is a strange power coming from the combination of his parents.
A plot could involve Ares testing Percy in a series of challenges that are not just about physical strength but also about his mental and moral fortitude. For example, Ares creates illusions of Percy's friends in danger, and Percy has to make difficult decisions. This would explore Percy's character deeper and also show a different side of Ares as a sort of cruel mentor. Or perhaps a story where Percy is accidentally transported to Ares' domain during a battle, and he has to find a way to escape while also dealing with the war - crazed creatures there.
A possible plot could be a competition among the demigods where Percy, as a 'Son of Ares' in this fanfiction, has to prove himself against other powerful demigods. The competition could include tasks like combat, strategy, and survival challenges. Along the way, Percy could learn more about the Ares - like qualities within himself and also form new alliances or rivalries.
A really cool plot could be Percy getting caught in an alternate dimension where Ares is the main god in charge. He has to find a way to survive in this new world, where the rules are different and he's seen as an outcast. Percy would need to use his wits and skills to navigate this strange place and find a way back home.
One idea could be Percy struggling to fit into Ares' violent and war - loving family. He might constantly have to prove himself in battles or challenges set by Ares. Another could be Percy having to deal with the other children of Ares being jealous of the attention he gets from their father. He could also be on a mission to redeem Ares' bad reputation among the demigods using his own unique skills and the powers he inherits from Ares.
Perhaps there's a mystery at Ares High School where strange things keep happening, like students getting sudden bursts of uncontrollable strength. Percy, suspecting it has something to do with Ares, investigates and discovers an ancient artifact hidden on campus that's causing the chaos. He then has to find a way to stop it without getting caught by the school authorities or Ares' minions.
One idea could be Percy struggling to fit into Ares' violent and war - like family culture. He's used to Poseidon's more fluid and adaptable ways. Another could be Percy having to face off against his new - found siblings in a sparring match to prove his worth to Ares.
There is definitely some out there. A lot of fanfiction writers like to explore unique pairings and family relationships in the Percy Jackson universe. Some might be more action - packed, while others could be more about the emotional journey of Percy as the son of Ares and Artemis. You might have to dig a bit through the search results to find the really great ones though.
Another plot could be that there is a mix - up between the Greek and Egyptian worlds. Percy, being the son of Horus in this fanfiction, is mistaken for a Greek demigod by some Egyptian deities. This leads to a lot of confusion and misunderstandings. Percy has to clear things up while also dealing with a threat that is looming over both worlds. He has to use his knowledge of both mythologies to save the day.
One common theme is identity. Percy has to figure out who he is with such an unusual parentage. Another is power. With Ares and Artemis as his parents, he might have unique powers that are explored in the stories. Also, there's often the theme of acceptance among his peers in the demigod world.