Leo Valdez

Leo is a character in The Lost Hero. Although Jason can not remember it, Leo tells him he that is his best friend. It's not quite clear if this is true or not, since as Gleeson Hedge stated, Jason has never before been in his class and everything the others think seems to be manipulation of the Mist.

Physical Description
Leo is described as looking "like a Latino Santa's elf". He has curly black hair, pointy ears, and a babyish face. He is thought by Jason to be hyperactive, as he could never stop moving his fingers.

The Lost Hero
Leo goes to Wilderness school together with Piper and amusingly also Jason. He works in team with Jason on their field trip to Grand Canyon, where they have to fill their work sheets on the skywalk. As a storm starts, all the kids can flee from the sky-walk except for Jason, Leo, Piper, Dylan and Hedge.

As Dylan turns out to be a Ventus and attacks the others with the help of two other venti, Leo is thrown off the sky-walk and slams into one of the canyon walls. While Jason and Piper try to fight back Dylan, Hedge, who turns out to be Satyr sent to protect Leo and Piper, rescues Leo. Hedge manages to get Leo back onto the sky-walk, where Dylan tries to abduct him. This is prevented in the last moment by Hedge, who is then abducted instead by the ventus.

Personality
Leo likes to play pranks on others, especially Coach Hedge, for which he uses his nearly impossible technical skills, such as manipulating Hedge's megaphone to frequently say "The cow says moo" and similar things. He was also able to build a small but working helicopter out of pipe cleaners, and seems to have fun at creating these small wonders. He also makes fun of other people by imitating them.

He was sent to Wilderness for running away from home six times, which hints that he has a bad relationship with his parent(s).