Cupid

"Oh, did you expect me to play fair? I am the god of love. I am never fair."

- Cupid Cupid is the Roman god of desire, affection, and erotic love. He is the son of the goddess Venus and her lover Mars but in some sources, he is the brother of Gaea. Cupid is also known in Latin as Amor ("Love"). His Greek counterpart is Eros. He is the frequent playmate of Hymenaios and Ganymede.

The Lightning Thief
While looking for Ares' Shield in the Thrill Ride O' Love, Percy Jackson and Annabeth Chase fall into a trap made by Hephaestus. Inside the ride, there are small Cupid statues with sharp arrows aimed at the duo.

The Son of Neptune
Cupid does not make a physical appearance, but he is mentioned. Frank Zhang and Percy think that Thanatos is Cupid. Thanatos states that he is frequently mistaken for Cupid. Thanatos mentions that Death and Love have more in common than people think.

The House of Hades
Cupid has Diocletian's scepter and refuses to give Jason Grace and Nico di Angelo the scepter until Nico admits something out loud. Nico attacks the invisible Cupid with Skeleton Warriors until Nico admits that he left Camp Half-Blood for love and admits to liking Percy. After Nico admits his feelings, Cupid turns visible and tells him that the only way to conquer love is to face it.

Appearance
In Percy Jackson's Greek Heroes, Cupid is described as "devilishly handsome", with the ability to alter his appearance, much like his mother Aphrodite.

In The House of Hades, Cupid is described as a lean, muscular young man with huge snowy white wings. He wears a simple white frock and jeans, and has his golden bow and quiver slung over his shoulder. His face is very handsome, but rather harsh as well, and "as difficult to look at as a spotlight." Cupid has shoulder-length straight black hair and blood-red eyes, as if "every valentine in the world were squeezed dry, distilled into one poisonous mixture."

Abilities
Cupid presumably possesses the standard powers of a god, though, as a son of Aphrodite and Ares, Cupid is very powerful.
 * Amokinesis: As the God of Love and desire, Cupid has absolute control and divine authority over love, lust, and desire, but not quite as much as his mother, Aphrodite. Cupid's form of love seems to be harsher and more enforced than Aphrodite's, which might be due to Cupid being a son of Ares.
 * Arrows of Romance: Cupid's power over love is usually exercised and enforced through his romantic golden bow and arrows. Anyone struck with Cupid's arrow will instantly be filled with uncontrollable desire and love for another (of Cupid's choice). This will even work on Olympians, shown when Cupid forced Apollo to fall in love with the nymph Daphne in Percy Jackson's Greek Gods. Due to these arrows of omnipotent allure, most of the gods, even Zeus himself, were wary of Cupid, as mentioned in Percy Jackson's Greek Heroes. If Cupid's arrows miss a target, they will glow white-hot and explode in a "geyser of flame", as seen in The House of Hades. However, when it does hit a target, the arrow dissolves, leaving no blood or visible wounds, though Nico's face did depict pain on the impact. The only known deities who have at least partial immunity to the romantic effect of Cupid's arrows are the three Virgin Goddesses: Hestia, Athena, and Artemis.
 * Coerced Romantic Confession: As shown in The House of Hades, Cupid can also force anyone to confess their true romantic feelings, and can always tell if the person is lying. The only known one Cupid did this to was Nico di Angelo, with the latter being forced to tearfully admit his secret love for Percy Jackson.
 * Romantic Omniscience: As seen in The House of Hades, Cupid, as the god of love, always knows who a person is actually in love with.
 * Beauty and Allure: As the God of Physical Attraction, it is mentioned in Percy Jackson's Greek Heroes, that much like his mother Aphrodite, Cupid can change his appearance at will, depending on the perception of beauty of the person he is in the presence of.
 * Invisibility: Cupid can render himself invisible in order to assault others unexpectedly, as seen when he first meet with Psyche in Percy Jackson's Greek Heroes, and when Nico and Jason faced him in The House of Hades. He cannot, however, will himself to become invisible while sleeping, which is why Psyche finally manage to see his face.
 * French: As a son of Aphrodite and God of Love, Cupid is fluent in French due to it being the "language of love".
 * Archery: Which not quite as skilled in archery as Apollo and Artemis, Cupid is still quite an impressive archer, due to his long experience at striking others' hearts with his arrows of omnipotent allure.
 * Disembodied Spirit: In Percy Jackson's Greek Heroes, since his physical body was far to weak for him to travel, Cupid sent his spirit out after Psyche, and briefly communicated with her as a disembodied voice.

Attributes and Attendants
Cupid's main and most infamous attributes are his romantic golden bow and arrows, which he can use to fill almost anyone with uncontrollable desire and love for another (of Cupid's choice).

As mentioned in Percy Jackson's Greek Gods, Cupid is sometimes accompanied by quite a few Erotes — miniature winged love gods.

Trivia

 * As mentioned in Percy Jackson's Greek Heroes, Cupid's ability to make others fall in love with anyone makes him one of the few beings that Hera, Demeter, and even Zeus himself actually fear.
 * Cupid is the brother of Timor and Metus, and the half-brother of Piper and Frank.
 * Cupid's form of love seems to be harsher and more enforced than Venus'. This might be due to Cupid being a son of Mars.
 * Ultimately, Cupid is the one who finally forces Nico to reveal his secret and passionate love for Percy.
 * Cupid is the only god who visibly scares Nico, since the latter is utterly terrified of somehow exposing his homosexuality.
 * According to Cupid, his counterpart, Death (Thanatos) can sometimes be kinder.
 * His closest equivalent in Bible is Asmodeus, the demon of lust and not only is responsible for twisting people's sexual desires but the same dangerous presumably.
 * "Erotic" comes from the word "Eros", Cupid's Greek name. Hence, Cupid is the god of erotic desires.
 * Cupid is also sometimes called Amor in Latin.
 * Eros might be a younger Cupid, as Eros appears as a baby. This could be untrue, because Gods can change their appearance.