Leo Valdez

 Leo is described by Jason to look like a "a Latino Santa's elf," with curly black hair, dark brown eyes, pointy ears, a cheerful, elf-like face, normally with a mischievous and impish smile on his face, and a diminutive stature with a slim and relatively scrawny build. He is 5'6! about the same height as Piper McLean. Leo's most notable trait is that he has a look in his eyes that makes him look like he has taken much more caffeine then the normal limit; this could be linked to his ADHD, although he is described as being even more ADHD than other demigods according to Annabeth.