Rick Riordan could totally make Percy the villain in a future book series
Think about it, if he spent more time acknowledging that Percy is really big on revenge and likes to inflict inhumane amounts of pain to anyone who slightly threatens the people he loves, and in some instance LAUGHS as he watches them suffer.
It was first mentioned in SoM that his fatal flaw is fatal loyalty and thatās what lands him in Tartarus.It gets to points when he goes overboard and genuinely scares the people he is fighting for (annabeth taking a step back from him when Percy chokes a monstress with her own poison in HoH). Or how when him and his mom literally KILL his abusive step dad in TLT, he is really happy about it but he regrets not being the one to have given the final blow to finish Gabe off for good.
Or how during SoN when heās traveling with Frank and Hazel through the north west to get to Canada, Rick made the point that they werenāt bothered by gangs while going through those rough neighborhoods because Percy was just THAT threatening.
The reason why Percy fights for camp half blood is because itās his found family there. He could care less about saving the world if it didnāt really affect him, even though he would most likely not admit it. He could care less about quarrels between the Gods, but him and his friends keep on getting wrapped up in it.
With the people he trusts it's easy to see him in his happier, goofier, joker side. But with strangers and people he doesnāt know, he has this blank almost angry expression. You know how cold and intimidating Percy was to like Leo, Piper, and Jason until he understood that Annabeth trusted them and he decided their his friends in MoA?
Heās a little overpowered being the son of The Big 3 as well and keeps on pushing himself to unlock new abilities that get more frightening as he grows into his powers. When he says āwhyā when Apollo shows up at his door isnāt really meant to be played for laughs, it's just that heās so DONE and so ANGRY at the gods.
As he grows up, he starts to align more and more with the radical ideologies that Luke had. Luke and Percy arenāt that different after all with what they think about the Gods. Luke was just willing to betray everyone who trusted him and kill his own found-family to achieve his revenge. If Percy wasnāt doing all he could to protect what he loved, nothing would stop him from being able to rip apart Olympus with his bare hands.
Iām just saying all it really would take for Percy to completely snap is to go overboard and accidentally scare away/hurt someone he loves, or have one of them die and have him be unable to save him, the most impactful examples being; annabeth, sally, his little sister, and possibly Grover (a lot of people overlook their friendship :c ) So yes, Percy just needs a little push to send him over to him embracing his dark side.
I predict that when he finds about Jasonās death heāll be really upset and blame Apollo, one of the Gods who keep on ruining their chances of a normal life (remember Jason was just trying to pass his classes and stuff until Apollo came and asked for his help.) Jason is similar to Percy in power and leadership, but Jason agreed to help because he believed it was the right thing to do and he was raised at camp Jupiter with the values of honor, duty, and serving the Gods. Percy would have said no, and he DID say no in TOA book one.
Because he doesnāt do what he does because itās the right thing to, but because in saving everyone he gets to save the ones he loves as well. He made the decision he would rather to let the world be taken over by the giants instead of letting annabeth fall to Tartarus on her own. He didnāt think they would survive. He just wouldnāt leave her. This has been my dark!percy analysis, thank you for coming to my ted talk