Thinking about how Michael Yew presumably drowned and then Percy dragged Will away to heal Annabeth.
Will reflects back on the moment several weeks later like "huh. Y'know if Annabeth drowned Percy would've absolutely gone beserk and flooded the entirety of Long Island. Not to mention he could've used his powers to sense where Michael was in the water and save him. Oh well. Priorities I guess."
But Will can't voice thoughts like that. Not without every other camper jumping down his throat about how "Percy is a hero! He made a tough call! It was a war! Michael was his friend!"
And that's fine. He didn't blame Percy for Lee or Michael's death, not really.
Heck, for a while it was as if Percy could do no wrong. Always cool. Always cute. Power couple on camp with Annabeth. And yeah, Percy was a little self-righteous at times. Still, he was an annoyingly good person. He was only ever nice to Will.
So Will never found it in himself to hate Percy, not really.
Then he disappears. A new prophecy is being fulfilled. Apparently Roman campers exist and try to attack camp. And Will finally gets the attention of someone he lowkey had a crush on shortly after the Battle of Manhattan: Nico di Angelo. Score.
And then. Oh, and then. Nico confesses he used to have a crush on- no. Used to be in love with Percy. Well. Isn't that interesting.
It takes a minute for Nico to convince Will he isn't a second choice, that he isn't just some constellation prize, runner up, since Nico can't have the great and powerful Son of Poseidon. (Aka the "strongest demigod Nico has ever met")
Still, Will wasn't jealous of Percy, not really. Not any more than anyone else at camp at least
But then... then Will hears stories. He gets every tale, every detail from everyone's point of view. Not always directly, but eventually all info gets passed around the infirmary. The medics hear all the gossip. And Nico opens up and confesses to Will as well.
And Will hears how Percy treated Nico. Over and over how their complicated relationship and Nico's crush and Percy's short temper... the time Percy choked Nico. The threats. Percy saying they should leave Nico to suffocate to death in the jar. The wonder bread. The gossip aboard the Argus II spread by Percy, leading the others of the 7 to find Nico "creepy" and not trust him. The horrible way he was treated again and again... All the while Nico sacrificed everything for him, multiple times. Percy would have never defeated Kronos or survived Tartarus without Nico.
And yeah, it was more complicated than that. Yeah, Will was biased. Nico wasn't exactly perfect either, but that didn't matter.
Because suddenly Will did blame Percy for Michael's death. His jealousy turns to resentment. Percy didn't deserve to have Nico's affections, past or present. Percy who acts like he's always in the right, Percy who everyone fawns over, Percy the hero of every story he's in, Percy who hurt the person Will Solace loves more than anyone...
Will smiles when they interact, all jokes and singalongs and sunny laughter and friendly conversation. But deep down the anger keeps growing.
Will Solace hates Percy Jackson.