Kayla Knowles

Kayla is an Apollo demigod, a daughter of Apollo.

History
Kayla is among the Campers that go to New York City and fight for the Olympians. She and her half-brother Austin set traps along the Brooklyn Bridge with their half-brother Michael Yew directing them.

Kayla sees Percy kill the Minotaur for a second time, this time with his own axe. After Percy was done destroying the monster army that was on the bridge, she, Austin, Michael Yew, and the rest of their cabin ran behind Percy, trying to drive the monsters back to Brooklyn.

She then saw Luke, possessed by Kronos. Percy ordered a retreat, and they ran. They had to fight other demigods, possibly old camp friends to get off the bridge. Kayla probably tried to injure them rather then kill them, as Percy and Annabeth did.

Ethan Nakamura tried to kill Percy, and would have killed him in his Achilles heel if Annabeth didn't jump in the way and take the knife for him.

Kronos fought with Percy, but when he saw that he had bathed in the river Styx, he hit the bridge with his scythe, and a wave of pure force blasted everyone backward.

Most of the Apollo campers had almost made it to the end of the bridge, when Michael Yew got Percy to break the bridge between them and Kronos. He did, but Michael Yew fell off the bridge when he did, and died.

Kayla survived, and and was commanded by the new cabin counselor Will Solace, her half-brother, to look for Michael Yew. They managed to find his body, and took it back to Camp Half-Blood after the battle.

It is not known if Kayla survived the battle, but she isn't mentioned among the casualties, so it is safe to assume she survived.