You left to join Kronos. That was two years ago. After you lost trust in the gods. But Percy told the younger campers you were one of the best people alive. He tells them about the fights you two fought together, how you saved him so many times. He may have overexaggerated on some of them but he didn't care. Percy wanted them to know about the good you. Not the bad you.

During the Battle of Manhattan, you came back to their side. After seeing the truth behind Kronos, you didn't want to die fighting for the wrong reason.

After the battle, which you somehow survived, you were accepted back with cheers and hugs. After the celebration for winning back at camp, Percy took you to the lake. He led you underwater, making an air bubble around you so you could breathe. You got a decent ways under the water and he pulled you into his arms, stuck his head in the air bubble, and kissed you.