Sailor Moon fans have long known that Queen Serenity is the mother of Princess Serenity, but who was the father? And what about the other Princesses? The only other parent mentioned is the Titan Kronos, God of Time, and his relation to Sailor Pluto. Yet the others remain pretty elusive.
But, based on the fact that the two named parents are based on the Greek pantheon, there are plenty of likely candidates to consider. Of course, without anyone named in-canon, this is all speculation, but the stars align just right for these Greek deities to be kin with anime’s favorite celestial guardians.
Princess Serenity's Father
Queen Serenity has stated that she is known as the Titaness Selene on Earth, so it’d make sense for another Titan to be Princess Serenity’s father. One likely candidate is the father of the sun, moon and dawn: the Sun God Hyperion. The Sun is the only major celestial body besides Earth with no corresponding Sailor Guardian, so there’s a chance Princess Serenity is the Guardian of both the sun and moon.
This theory is shaky, given that Helios essentially fills that role, while also being the son of Hyperion in the original stories. It’s also possible that Queen Serenity used the power of the Silver Crystal to create Princess Serenity, a la Wonder Woman. Given how little is known about the Silver Crystal’s abilities, it’s fairly likely.
Princess Mercury's Parents
Considering Mercury’s water-based powers, it’s entirely possible that her mother was the Titaness Metis, Zeus’ first spouse and the one who helped him free his siblings from Kronos. Metis was the Goddess of Wisdom before her daughter Athena, a non-Titan candidate for Mercury’s mother, was. Mercury’s mother could also be Tethys, Titaness of Freshwater.
This makes sense given that, if Neptune represents the sea, Mercury could represent freshwater. The most obvious father would be Hermes, given Mercury’s lyre-like harp, which Hermes -- also known as Mercury -- is credited for creating. However, the lyre is mostly attributed to Apollo. Oceanus, Titan of the Sea and Water, is also a possibility, or even the Titan of Intelligence, Coeus.
Princess Mars' Parents
Mar’s father is most likely Ares, aka Mars, God of War. However, given Rei’s penchant for ravens and divination, Apollo is also a likely candidate, as ravens and clairvoyance are associated with him. As the God of the Sun and archery, Mars could have inherited her fire powers from him. A Titan option could be Prometheus, was who punished for giving fire to humanity. Pathos, the God of Passion, is also a possibility as Mars sometimes introduces herself as the Guardian of Passion.
Athena could be her mother, given that she is a war goddess. However, there's another lead in the rare Original Picture Collection Volume Infinity, where Naoko Takeuchi mentions that Mars was going to be associated with the Goddess of Night Nyx, so it’s possible that she’s the mother.
Princess Jupiter's Parents
Jupiter’s lightning powers could come from being a daughter of Zeus, aka Jupiter. There aren’t any Titan equivalents other than Typhon, God of Storms, so there’s little room for speculation on her father. Her plant association, however, leaves many options.
Looking at likely Titan lineages, her mother could be Gaia, the primordial mother of the Earth. There’s also Persephone, who brings the growth that comes with spring. There’s also Chloris, Goddess of Flowers, and Hegemony, the goddess who makes plants bear their fruits.
Princess Venus' Parents
Aphrodite is most definitely Venus’ mother, so her likely father would be Hephaestus, the blacksmith to the gods. This would explain why Venus is so capable in combat and the leader of the Sailor Guardians, as her father could have trained her. Her father could also be Eros, as while he is normally known as Aphrodite’s son, the Theogony -- one of the most ancient texts in regards to myths -- claims that he is a primordial being with little relation to Aphrodite.
Like with Mars, Pathos is also a passion-related candidate for fatherhood. Her father could also be Himeros, who represents desire and unrequited love, and is known for carrying a tainia, a traditional Greek headband made of leather or ribbon worn by athletes. Given Minako’s horrible luck with love and her iconic ribbon, Himeros seems like a perfect fit.
Princess Saturn's Parents
Hades and Persephone are the most likely parents of the Princess of Death and Destruction, but they’re not the only options. In Greek mythology, Thanatos was the personification of death, and given how destructive Saturn’s powers are, it’s highly possible he’s her father. Kronos, also known as Saturn, could also be her father, but that’s mostly because of the name. Perses, the Titan God of Destruction, is another good option. Even his name means “to ravage” or “to destroy.”
As for Saturn’s mother, Eris, Goddess of Chaos, is a likely candidate. Hecate, Goddess of Witchcraft, could also be Saturn’s mother. She is also known as the gatekeeper between this world and the next, and thus is known as a Goddess of the Underworld.
Princess Uranus' Parents
Uranus’ father is likely, well, Uranus -- but there is one other possibility. Aether was Uranus’ father and the God of Light, Space and the Heavens, which Sailor Uranus’ powers come from. Her mother is a bit trickier to figure out.
Unlike the Inner Guardians, there isn’t really an overt association to go on. Uranus' mother could be Hera, Queen of the Heavens, who is associated with air and constellations. It’s also possible her mother is a lesser being like the Aurai, the breeze nymphs.
Princess Neptune's Parents
Poseidon would be the best possibility for Princess Neptune, with his wife Amphitrite being the mother. If Neptune’s father is a Titan, Oceanus is the best candidate, making her mother Tethys. Another Titan mother could be Mnemosyne, Titaness of Memory who is known as the precursor the the muses, Goddesses of Music. This would explain Michiru’s musical skills. On the other hand, Aphrodite is associated with mirrors, which would tie into Neptune’s Deep Aqua Mirror.
Princess Pluto's Parents
While Kronos is the confirmed father of Princess Pluto, we still don’t know her mother. Rhea was Kronos’ wife in the myths and represented the eternal flow of time, so she is most likely Pluto’s mother. Mnemosyne would, again, be a great candidate, being associated with not only memory, but also time.