|“||Oh, did you expect me to play fair? I am the god of love. I am never fair.||”|
–Cupid to Jason Grace in The House of Hades.
Cupid (also known as Amor in Latin) is the Roman god of erotic love, affection, and desire. He is the lieutenant of his mother, Venus/Aphrodite. He is the frequent playmate of Hymenaios and Ganymede. His Greek counterpart is Eros.
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.
Cupid does not make a physical appearance, but he is mentioned. Frank Zhang and Percy Jackson 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; meaning that both can be beautiful or harsh, depending on how a person looks at it.
Cupid has Diocletian's scepter and refuses to give Jason Grace and Nico di Angelo the scepter until Nico admits his crush stating that the person that he care about the most is in Tartarus. Nico attacks the invisible Cupid with Skeleton Warriors but still urging Nico to admit his crush. Finally, Nico admits love and feelings for Percy. Nico had fled Camp Half-Blood after Bianca's death not just because he felt rejected by the other campers as the son of Hades, and not just Percy had let him down by failing to keep Bianca safe--he had romantic feelings for Percy (not Annabeth), which he could not deal with. After Nico admits his feelings, Cupid turns visible and tells him that the only way to conquer love is to face it.
In both of his forms, Cupid enjoys and knows how unpredictable his domain is. He can be quite vengeful if someone offends him, as was shown by how he shot Apollo after he made fun of his archery skills and appearance in the myth of Daphne. However, Cupid shows pity for others and admires endurance, a trait his beloved wife Psyche possesses.
In Percy Jackson's Greek Heroes, Eros is described as "devilishly handsome". His appearance changes in the way his mother's does: It changes to appeal to each person who gazes upon him.
In The House of Hades, Cupid is described as a lean, muscular young man with snowy white wings, and he wore a simple white frock and jeans, with a bow and quiver slung over his shoulder. He has straight black hair, blood-red eyes that looked as if "every valentine in the world were squeezed dry, distilled into one poisonous mixture", and a face that was handsome but also harsh - "as difficult to look at as a spotlight". His voice is described as rich and deep, but threatening like a tremor before an earthquake.
As a son of Venus and Mars, Cupid is very powerful. In spite of the fact that he is a minor god, his omnipotent romantic allure makes most of the gods, like Demeter, Hera and even Zeus himself actually fear him. The only known deities who have at least a partial immunity to him are the Virgin Goddesses.
- Amokinesis: As the God of Erotic Love, Affection, and Desire, Cupid has absolute control and divine authority over love, lust, and desire, but not quite as much as Venus/Aphrodite. He cannot create love from nothing. His form of love seems to be harsher and more enforced than his mother's, which might be due to Cupid being a son of Mars/Ares.
- Arrows of Romance: Cupid's power over love is usually exercised and enforced through his romantic golden bow and arrows. Anyone struck with his arrow will instantly be filled with uncontrollable desire and love for another, which he can choose. In Percy Jackson's Greek Heroes, he forced Apollo to fall in love with the nymph Daphne.
- Arrows of Coerced Romantic Confession: As shown in The House of Hades, Cupid can force anyone to confess their true romantic feelings by shooting them through his arrows. He 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 was for Percy Jackson.
- Romantic Omniscience: Cupid always knows who a person is actually in love with. This is seen in The House of Hades.
- Beauty and Allure: As the God of Desire, Cupid can change his appearance at will, depending on the perception of beauty of the person he is in the presence of.This is mentioned in Percy Jackson's Greek Heroes.
- Archery: Which not quite as skilled in archery as Apollo and Artemis, Cupid is quite an impressive archer on account of his long experience at striking others' hearts with his arrows.
- Magical Arrows: Apart from his love power, Cupid's arrows possess magical powers. If his arrows miss a target, they will glow white-hot and explode in a "geyser of flame", as seen in The House of Hades. When his arrows hit a target, the arrow dissolves, leaving no blood or visible wounds, though Nico's face did depict pain on the impact.
- French: As a love god, Cupid is fluent in French due to it being the "language of love".
- Invisibility: Cupid can render himself invisible in order to assault others unexpectedly. He cannot, however, will himself to become invisible while sleeping. This ability is first shown in Percy Jackson's Greek Heroes when he lived in a villa with Psyche. In The House of Hades, he became invisible when Nico and Jason faced him.
- Disembodied Spirit: As seen in Percy Jackson's Greek Heroes, Cupid can send his spirit to other locations. He sent his spirit out after Psyche and briefly communicated with her as a disembodied voice since his physical body was far too weak for him to travel.
Cupid's main and most infamous attributes are his romantic golden bow and arrows.
As mentioned in Percy Jackson's Greek Gods, Cupid is sometimes accompanied by quite a few Erotes — miniature winged love gods. His main attendant is Zephyros the West Wind, who is under Aphrodite's protection in exchange of his service.
- Cupid is the only god who visibly scares Nico.
- Cupid is a moon surrounding Uranus (planet) that was discovered in 2003 and is named after him.
- According to Cupid, his counterpart, Death (Thanatos), is very much similar to him, but can sometimes be kinder.
- "Erotic" comes from the word "Eros", Cupid's Greek name. Hence, Cupid is the god of erotic desires.
- Among the Greek gods, he is the only one who is just as shrew his Roman side when appearing.
- His Norse equivalent is Balder.