Not sure which book you're talking about, but in the first book, he surprises everyone by starting off really suckish, then getting really good after a quick refreshment.
Details: Luke and Percy were dueling with swords, and at first, Percy wasn't any good. When Luke called a break, everyone went over to the drinks cooler. Luke poured ice water on his head to cool himself down, and Percy did the same. Since Percy is the son of Poseidon, water can give him energy or heal his wounds. Luke then showed everyone a disarming technique, and started dueling Percy again. Because Percy had touched water earlier, his senses opened up and he had more energy. Percy got a lot better at the sword, and even though everyone else thought it was amazing, Percy thought Luke would pwn him soon, so he decided to try the disarming technique since he had nothing to lose. The move worked, Luke's sword got knocked out of his hand, and the other campers stared at Percy in awe.
Sorry this explanation is very clear. I'm not good at putting things into a summary.
After Percy's fight with Clarisse during the game of Capture the Flag, they start to discover that who his dad was because he started healing in the water when Poseidon claimed Percy
he did'nt fight anyone
Percy suprises everyone by beating Luke, who was "the best swordsman in 300 years" when it was his first time. He is able to do this because, even though it is not revealed til later on in the book, he is a son of Poseidon thus when watertouches him, it gives him special abilities.
Water gives Percy Jackson renewed strength during the sword fight. Luke was surprised and angry.
Near the end of the book Percy Jackson and his friends escape from Hades', King of the Underworld, lair. Then he confronts Ares, Clarisse's dad, and defeats him after a battle. When everyone goes back to camp Luke reveals to Percy that he was the Lightning Thief.
Medusa
Percy and Jason fight in Mark of Athena on page 22.
why can't percy fight crusty
Percy has to fight a minotaur and he loses his mother
Because he wanted to find out his position in camp. Plus, he had been in plenty of fights, so he thought he coudl handle Clarisse. He wanted to show everyone that he could stand his ground and fight.
sword fight
Percy and Annabeth do fight sometimes (rarely), and usually, their fights are about something small, for example, they have fought about Rachel before (4 Percy Jackson book). Annabeth and Percy do fight though rarely, most times they are okay with what each other thinks.