Board Thread:Percy Jackson & the Olympians/@comment-27799899-20170122231450

In the trivia section of the percy jackson page it says that percy has fought 5 titans, but for the life of me i can figure out the 5th one, he has fought: Kronos, Hyperion, Iapetus, Atlas, and the other i have no idea. Can anyone help me out?

i think i'm posting in the right place for this kind of inquiry, but if i'm not please tell me 