"The problem, I couldn't find a blade that felt right in my hands" (p.109). Percy couldn't hold his sword, he was fighting it. the sword was technology.
Ch.8 Character vs. Society
"'We'll pulverize you,' Clarisee said, but her eye twitched" (p.89). Percy was going to fight Percy.
Ch.8 Character vs. Nature
"Then something happened. I felt a tug in the pit of my stomach. I heard the plumbing rumble, the pipes shudder" (p.91). Percy couldn't control his self power, he was fighting himself.
Ch. 8 Character vs. Fate
"'But see, we don't care about the flag. We care about a guy who made our cabin look stupid" (p.121). Percy, being the character, was about to fight the Ares cabin, the society.
We came to beat you up boi.
"I came out of the creek and immediately felt the bone tired. My arms started to go numb again, My adrenaline rush left me" (p.124). Percy is fighting him being affected by water, which would be nature.
Hey guys, look, he is a water bender.
"By the time I looked up, the sign was already fading, but I could still make out the hologram of green light, spinning and gleaming. A three-tipped spear: a trident" (p.126). Percy has to fight his fate knowing that because he is related to one of the main gods, it is going to be harder for him to train and be a normal camper.