Cupid

Cupid is Eros' Roman form. Possibly like other Olympians as Cupid he becomes more disciplined as well as more militaristic and warlike.

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.

Appearance
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.