Cupid

Cupid is Eros' Roman form. Possibly like other Olympians as Cupid he becomes more disciplined as well as more militaristic and warlike. He is a well known icon for Valentine's Day.

The Son of Neptune
Cupid does not make a physical appearance in the book but he is mention by Thanatos who is frequently mistaken for him.

Apperance
In most paintings and sculptures Cupid is portrayed as a chubby winged toddler often wearing a diaper and other times he is a slender winged youth. He is usually holding a bow which shot arrows make people fall in love when struck by one.