Then Nyx, somehow all by herself, had a daughter named Hemera, who was Day. Those two never got along because they were as different as . . . well, you know.

Percy Jackson, in Percy Jackson's Greek Gods

Hemera is the Greek Primordial Goddess of the day. She is the daughter of Erebos and Nyx. She is the female counterpart of her brother and consort, Aether (Light), with whom she had one child: Thalassa, a Protogenos of the Sea. Her Roman aspect is Dies.

Percy Jackson's Greek Gods

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Nyx, her mother.

In the evening Hemera's mother Nyx drew a veil of darkness between the shining atmosphere of Aither and the lower air of earth (Chaos) bringing night to man. With each morning Hemera dispersed night's mists, bathing the earth again in the shining light of heaven (Aither). In the ancient cosmogonies night and day were substances distinct and quite independent from the sun.

Hemera was closely identified with Hera, the Queen of Olympus, and Eos, goddess of the dawn. Hesiod appears to regard her as more of a divine substance rather than anthropomorphic goddess. She was largely irrelevant in mythology, with her role being wholly subsumed by the goddess Eos.

Pausanias seems to confuse her with Eos when saying that she carried Cephalus away. Pausanias makes this identification with Eos upon looking at the tiling of the royal portico in Athens, where the myth of Eos and Kephalos is illustrated. He makes this identification again at Amyklai and at Olympia, upon looking at statues and illustrations where Eos (Hemera) is present.

Percy Jackson's Greek Heroes

Hemera is briefly seen by Phaethon, when the latter visits the palace of his father Helios.

The Heroes of Olympus

The House of Hades

When confronting Nyx, Percy Jackson and Annabeth Chase pretended to be tourists, unimpressed by the Primordial of Night. But they added that Hemera might be more interesting. Offended, Nyx snapped that Hemera (Day) was her daughter, and that Night was much more impressive than Day.


In Percy Jackson's Greek Heroes, Hemera is described as a beautiful woman in shimmering blue-and-gold robes.


She presumably has a goddess' powers, but is extremely powerful, as she is one of the Protogenoi.

  • Pyrokinesis: As the Primordial Goddess of Day, she has divine authority and control over fire.
    • Heated Fire: Hemera can control the heat of her fire. It is unknown if she can wield Greek Fire.  
    • Fire Extinguishing: She can put out any amount of fire without losing energy
    • Fire Blasts: It is assumed that Hemera can launch projectile blasts of flame at opponents.
    • Fire Cape: It is possible that Hemera can appear or disappear in columns of flames
  • Photokinesis: As the Primordial Goddess of Day, she has absolute control over light.
    • Create illusions/hallucinations.
    • Create light shields/force fields.
    • Project healing energies (different from Vitakinesis).
    • Blast of light to impale or blind enemies for some time or maybe forever.
    • Create a ball or shape of light to blast.


  • In different myths, Hemera is a daughter of Nyx and Chronos (Time), and the mother of Ouranos and Gaea.
  • Her Norse equivalent is Dagr.
The Heroes of Olympus
Core Series: The Lost Hero | The Son of Neptune | The Mark of Athena | The House of Hades | The Blood of Olympus
Main Characters: Jason Grace | Piper McLean | Leo Valdez | Percy Jackson | Frank Zhang | Hazel Levesque | Annabeth Chase | Reyna Avila Ramírez-Arellano | Nico di Angelo | Gleeson Hedge
Minor Characters: Rachel Elizabeth Dare | Thalia Grace | Octavian | Fleecy | Dakota | Ella | Tyson | Mrs. O'Leary | Arion | Hylla | Bob | Calypso
Olympian Gods: Zeus | Hera | Poseidon | Hades | Ares | Demeter | Athena | Apollo | Artemis | Hephaestus | Aphrodite | Hermes | Dionysus
Minor Gods: Achelous | Aeolus | Asclepius | Boreas | Eurus | Hecate | Iris | Hypnos | Keto | Khione | Kymopoleia | Mithras | Nemesis | Nike | Notus | Phorcys | Serapis | Thanatos | Triptolemus | Zephyros
Roman Gods: Jupiter | Juno | Neptune | Pluto | Mars | Minerva | Ceres | Lupa | Bellona | Fortuna | Janus | Terminus | Vulcan | Mercury | Pomona | Aquilon | Hercules | Cupid | Auster | Favonius | Letus | Victoria | Orcus
Giants: Enceladus | Porphyrion | Alcyoneus | Polybotes | Ephialtes | Otis | Damasen | Clytius | Mimas | Orion | Hippolytus | Thoon | Periboia
Undead: Medea | Midas | Lityerses | Gray | Phineas | Otrera | Echo | Narcissus | Sciron | Pasiphaë
Primordial Gods: Gaea | Tartarus | Ourae | Nyx | Chaos | Ouranos | Akhlys | Erebos | Hemera | Elpis | Spes
Companion Books: Percy Jackson and the Olympians | Demigods and Monsters | The Ultimate Guide | The Demigod Files | The Demigod Diaries | The Son of Sobek | The Singer of Apollo | The Staff of Serapis | Percy Jackson's Greek Gods | Percy Jackson's Greek Heroes | The Crown of Ptolemy | Demigods & Magicians | Demigods of Olympus