Are Sailor Lethe and Sailor Mnemosyne Sisters?

Sailor Lethe and Sailor Mnemosyne

Sailor Lethe and Sailor Mnemosyne

Though hardly on the same level of the brutal Sailor Moon debates we’re used to dealing with here on this blog, the subject concerning the connection between Sailor Lethe and Sailor Mnemosyne is one of those seemingly simple issues that the fans can never quite agree on.

If these two are sisters, then that opens up a whole new slew of questions, such as the nature of their seemingly romantic relationship and how two related people could each have their own Sailor Crystal. If they aren’t, why do they look so much alike??

Today we’ll be taking a look at Sailors Lethe and Mnemosyne — the so-called “sister Senshi” — to see if they really are related, and just what’s going on with all this Sailor Crystal confusion. You might want to grab a science book, because this whole issue is about to get astronomical!

Sailor Lethe stands her ground

Sailor Lethe stands her ground

The concept of Sailors Lethe and Mnemosyne being twin sister is, on the surface at least, not all that much of a surprise. For those of you who are perhaps new to Sailor Moon,1 the series actually has quite a few twins in it. So many, in fact, that there are around ~10 pairs of twin (or twin-like) characters in the series.

So let’s just get the first question out of the way, shall we?

Yes, Sailor Lethe and Sailor Mnemosyne are undeniably and canonically twin sisters. Ms. Takeuchi kindly answers this question for us in the Materials Collection artbook where she outlines their characters: right between the two of them is the word ふたご (futago; twins).2

Judging by the way that they act toward each other, I guess you could argue that they’re meant to be lovers. As for the logistics of how that one works out, that’s kind of beyond the scope of this blog, but hey — love knows no boundaries in this world of miracle romances, right? Not even those pesky laws surrounding university Mamoru and junior high schooler Usagi!

Since we’ve got the easy question out of the way, that leaves us with the hard one: how is it possible for twin sisters to both have their own Sailor Crystal?

We're about to do some Sailor Crystal math here...

We’re about to do some Sailor Crystal math here…

Strictly speaking, the generally accepted rule is that each celestial body has one Sailor Crystal. This is at least a reasonably accepted fact considering that Sailor ChibiMoon comes back from the future with the Moon Sailor Crystal.3 It’s a bit unclear how the passing of the torch to the new generation actually works, seeing as how you kind of die when you lose your Sailor Crystal, but I guess you could argue that Usagi also has the whole Sailor Cosmos thing going for her, so we’ll leave that be for now.

In order to deal with this issue, we’ll need to actually figure out just what Lethe and Mnemosyne are, then.

Though often misreported on fan sites as being from sister planets, Sailor Lethe and Sailor Mnemosyne actually lived on the same planet in a binary star system.4

Think something like Tatooine in Star Wars,5 just if Luke had a twin sister that he was romantically… involved… hey, wait!

Time for introductions!

Time for introductions!

I won’t bore you with the details on how all this planet vs. star confusion comes into play since I already covered it when discussing the issue of whether Kinmokusei is a planet or a star, but to be fair, it’s a pretty honest mistake. Regardless of how the mistake came into being, though, Sailor Lethe and Sailor Mnemosyne both introduce themselves as being the respective guardians of the Lethe Star and Mnemosyne Star,6 so there’s really no opening for debate here.

Lethe: 私は忘却の川の番人 レテ星(スター)のセーラーレテ。

Mnemosyne: 私は記憶の川の番人 ムネモシュネ星(スター)のセーラームネモシュネ。

Or, for the non-Japanese-speakers among us (translated literally):

Lethe: I am the guardian of the river of forgetfulness, Sailor Lethe, of the Lethe Star.

Mnemosyne: I am the guardian of the river of memory, Sailor Mnemosyne, of the Mnemosyne Star.

When referring to their respective celestial bodies, Ms. Takeuchi helpfully puts in a furigana7 guide above the kanji to clarify for the readers that these are, in fact, stars and not planets.

The Lethe/Mnemosyne binary star system

The Lethe/Mnemosyne binary star system

In case that wasn’t enough, the following page shows a picture of the binary star system as the two discuss how small and impoverished their planet was, this time referring to it as:8


Our planet was small and impoverished…

The text clearly indicates that it was “their” planet.9

What this all basically means is that the most likely explanation for this whole situation is that these two Sailor Soldiers were born on a small planet that orbited the twin stars Lethe and Mnemosyne. Since living on the respective celestial body doesn’t seem to be a prerequisite to become a Sailor Soldier, I don’t really see much of a problem with this whole situation. In fact, these two women being twins actually makes a lot of sense, considering the binary star system!

Yup, twins!

Yup, twins!

Yet again, this is another one of those situations we run across in Sailor Moon where I really wish we had more information on how the whole process surrounding Sailor Crystals works. I love the idea of there being twin Sailor Soldiers, but unfortunately the Sailor Lethe and Sailor Mnemosyne story arc takes place in a scant few pages, so we never really get a full picture of how they became Sailor Soldiers.

With that said, this whole issue does leave me wondering what the limits are on what kind of celestial body can have a Sailor Soldier. Planets, yes. Moons, yes. Dwarf planets (Ceres/Pluto), yes. Asteroids, yes. Taiki’s forehead, yes. Stars, yes. The whole cosmos? That too.

What do you think the limits are? Could there be Sailors of blackholes, comets, or even space dust?? I’d love to hear other people’s thoughts on the subject!

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  1. Hi!
  2.  See 双子 (
  3. There’s also the the totally-not-canon-though-kinda-canon-but-not-really Parallel Sailor Moon short story, where each of the Sailor Soldiers’ daughters take up their mothers’ respective roles, but that world has so many mysteries in it that we’re putting it aside.
  4.  See Binary Star (Wikipedia)
  5.  See Why Tatooine is plausible: the orbital mechanics of binary star systems
  6.  See p. 120 of vol. 17 of the original release of the manga
  7. Basically a guide for how to read a kanji; see Furigana (Wikipedia)
  8.  See p. 121 of vol. 17 of the original release of the manga
  9. Before you post a comment about what your Japanese/English dictionary says  星 means, please read the other article on Kinmokusei. Yes, I’m aware. No, it doesn’t always mean “star.”

20 thoughts on “Are Sailor Lethe and Sailor Mnemosyne Sisters?

  1. Fans have long made OCs for any object in space you can think of. Many are Senshi of lower-level things like flowers and the like. It’s not my personal favorite way to run with what seems to be a bit of an open-ended concept, but I digress… I think probably the biggest question to ponder over from the representation of star Senshi is whether there is or who might already technically be a ‘Sailor Sun’. (Though, don’t ask me why… That name always struck me as kind of awful XD.)

    I actually just wanted to say thank you so SO much for clearing up the star and planet words in those panels. I’ve heard of twin planets somewhere before but as far as I know twin stars are more common, and it’s neat to see that these two are a bit of a parallel to Chi & Phi.

    I have to disagree with the romantic side that you’re reading though… At least from the Kodansha translation of the manga, I never got the impression that they were lovers. Twins are normally *very* close to each other but unless the kanji you’re reading has seriously romantic/sexual (versus simply caring/close) overtones, I don’t think there’s anything else going on with them.

    • Fan OCs are… well, generally pretty absurd and don’t follow any of the rules of the way that Sailor Senshi are supposed to function, so I think we can pretty much rule that insanity out. =p
      But I am curious about what the limits are in-universe re: what can and cannot have a Sailor Crystal. Since the Asteroid Senshi are clearly only, that opens up a whole lot of room for interpretation.

      Phobos and Deimos are also a weird situation since they actually have nothing to do with the moons of Mars of the same name, and are actually not even Sailor Soldiers.
      There’s also the theory that the Starlights are actually the Sailor Senshi of comets and not actually any particular planet, but that’s another discussion for another side.

      Regarding the lovers interpretation — I’m not too passionate about the theory either way. We don’t have any hard confirmation in the Japanese text to say whether they are or they aren’t. I know that twins are close, but looking at the art and the panels, they still come off as a bit too close in my opinion to simply be a strong relationship between twin sisters. But again, I don’t really have any strong opinions on the subject.

      • If it’s just the art then I’ll remain unconvinced :p. I feel like it’s more of a fashion thing? Their outfits/hairstyles make them look more delicate and feminine so the art comes together well when they’re touching each other. Chi and Phi (another twin set for comparison) have the opposite look and personalities – powerful/masculine – so if they were to be all touchy-feely it might seem forced? But generally I think since there’s so little art for either pair that it’s hard to make conclusions just from that. So, I appreciate that you’re not super sold either way. Sorry to dwell on it ^^;;.

        Sorry this is usually the “copy” I have on hand but if MD is to be believed, Phobos & Deimos were “soldiers in training” (Vol 11 p.146) as well as being from the “planet” (*cough*STAR??!*cough*) Coronis (p.149). I get the whole raven – Coronis thing myth-wise (though it’s tying two myths together based on the name), but that star (whichever one it is in the Hyades cluster…) would be in Taurus. Mars is usually seen as ruling Aries.

        So, [Phobos & Deimos -> Mars] (names) and [Phobos & Deimos -> Coronis] (raven imagery) but I have no clue what ties these two equations together if anything *sigh*. Why in-universe Phobos & Deimos hopped over to join Sailor Mars from Coronis is just beyond me… (Just cause it’s from the nearest open cluster of stars to the solar system???) I think this was probably another case of them being introduced earlier with a more simple intent (Mars’ guides) which caused problems by reintroducing them in the Galaxia context and trying to fit them into the plot. (Though I do appreciate her trying to do so, I have to say!!) My daughter’s nap is over so I can’t look into it further atm sadly OTL. Looking forward to an article about it haha!

        • Nah, I really don’t have a horse in this race. =D If people think they’re romantically involved, then hey, sure! If they don’t, I can see that too. You’re right, though. Their relationship does seem pretty close to the one between Mio and Mayu (which was very much not romantic, but still showed a lot of the two sisters being reliant on each other) of Fatal Frame 2(Wikipedia) and less of one that was romantic in nature.

          Now, moving onto the soldier one!

          To be totally and absolutely blunt, the MD translations have… “accuracy issues” to put it generously. This whole star/planet problem with Lethe and Mnemosyne even stems from the MD translation, in fact. But we’re not talking about accuracy issues this time. Yaaaay!
          As for the “soldiers in training” phrasing, the Japanese word used here was 訓練兵, which literally means a military soldier who is still undergoing training. However, since Naoko usually refers to them either as “Sailors” (セーラー) or “Senshi” (戦士), the use of the word soldier (兵) implies to me that they weren’t exactly Sailor Soldiers in training, but rather normal soldiers training under the Princess of Mars.
          =D And the Japanese seems to imply that Coronis was a planet, so we’re good to go on that one.

          As the last issue re: why in the heck Phobos and Deimos came to Mars in the first place, I feel like this is the weakest part of the Sailor Stars story arc. Suddenly Luna and Artemis are space cats from the planet Mau? Phobos and Deimos come from elsewhere too? But why in the heck are space animal people coming across the universe just to serve in the court of the Moon Kingdom, despite not being under its control??
          The whole story line feels shoehorned in, sadly…

          • oooOOOooooh! Ah very cool :3. Thank you for clearing that up!!

            LOLOL space cats indeed XD.

    • I was always surprised there was never a Sailor Sun in the story. But I guess it’s just as well since I feel Naoko Takeuchi might have gone just a bit overboard with all the sailor senshi running around for all kinds of celestial bodies.

      • You could make a good argument for the fact that Mamoru would, in fact, be representing the Sun. Astrologically speaking he covers this, and the whole Golden Kingdom storyline (including Helios and others) have a lot of Sun themes.

          • I always kind of felt that the “Golden Kingdom” in the Dream arc was representative of a sun kingdom. ^^

        • I am sorry but I have to disagree with this. Mamoru can not be the Senshi of the Sun as he is all ready Senshi of the Earth and as you even say people can not be Senshi of more then one celestial object. The whole Golden Crystal and Golden Kingdom references were done to parallel Prince Endymion’s Kingdom with Princess Serenity’s Silver Millennium. It was also in about the say way only except in the way of a adversary that Sailor Galaxia’s Golden references were made to parallel Sailor Moon’s Silver references. Tuxedo Mask was only ever stated to be the Prince and Senshi of the Earth not the Sun. In fact in the 90s anime when Sailor Galaxia was talking about Sailor Moon’s friends and loved ones she killed it showed each Inner and Outer Senshi with their planet and their Star Seed. When it came to Mamoru it showed a picture of him and the Earth not the Earth and Sun with his Golden Starseed.

          • Apologies if my earlier comment wasn’t clear.

            I don’t think that Mamoru is the senshi (i.e., possessing the Sailor Crystal) of the Sun. But I believe that his character is meant to represent the Sun in addition to his role as holder of the Earth Sailor Crystal.

            Helios, the Golden Kingdom, the Golden Crystal… starting with the Dream arc, there are a lot of connections created between Endymion and the Sun.

          • That goes, however, a bit against the thinking in Japan that the sun is supposed to be red, not gold or yellow as in Western countries. And school does its best to drive that thinking home. In class five, all suns were properly red as they are supposed to be.

            Furthermore, the sun is supposed to be the …ehm… mother?… birthplace? of evil Metalia, a force so evil and strong that it had the power to destroy the world. Why should anyone want to associate good Mamoru with such an evil and impure place?

            No, I don’t think connections to the sun were intended. Earth and the Mond are a pair and opposites the same way as gold and silver are. Even in Japanese. So any references that could point to Mamoru being the the stand-in for the sun are imho only coincidental.

      • The sun spawned Metalia, evil incarnated. Why should it have a good Sailor Senshi? Because of that, I had always thought that suns are just outside the scope of celestial bodies that have their own guardian but, well, then 4 series later Lethe & Co. happened. It’s probably just not well thought-through.

  2. Thanks for this! I might need to go back and update my fansite a bit. I had it as twin planets, not twin stars watching over a singular planet. I’m gonna chalk that up to fan translations and the wikis. haha 🙂

    As for the romantic bit, I personally never saw it that way. I just get the impression that the two girls are opposites. Lethe seems aggressive, extroverted and is protective of her sister who in turn seems passive, introverted and maybe a bit naive. Plus i think having your planet destroyed and only having one another left in the world could have something to do with it.

    • It’s really too bad that the planet theory took hold this long, and seems to have spread across all wikis and fan sites. =( Kinda makes me wonder what other “accepted facts” in the Sailor Moon universe are misinterpretations.

      As for the romantic angle, I think I may edit that down in the article. I could see it either way and never really thought too much about it, but after reading all of the comments, it seems that the issue is much more debated than I thought. ^^

      • I believe Kousagi’s birthday is one such “accepted fact” that I recently ran into… This is why citations are so important and so incredibly sad that they’re underused. I’ll admit I’m guilty of that myself in my earlier efforts on wikimoon :/.

        • With the whole Parallel Sailor Moon story, you could basically make up anything you want about it and it could just as likely be fact. x_X Fortunately, it’s absolutely outside the bounds of canon and we don’t have to worry about it, but it does mean that there’s a lot of misinformation running rampant out there, and many people don’t seem to realize that it IS totally unofficial.

  3. This blog of yours is a gem. I read it almost on the daily and I can never get tired of your articles!

  4. I specifically waited to read the manga in the Eternal Edition for it’s most current/updated translation and notes (and ofc the color illustrations are my weakness), and I actually just finished the final arc yesterday!
    Lethe and Mnemosyne immediately fascinated me, as they are depicted in full color on the very first page. I did initially assume they were sisters based on their similar designs, but when I got to the chapter in which they’re featured I definitely interpreted them as lovers without question (mostly from the art, but I don’t think the text negates it either). I know that they are meant to represent twin stars of a single planet, but in the context of the story that’s sort of the role that all the inner/outer planets serve for the moon (and by extension, seems to be the moon’s role in protecting earth). So it doesn’t really strike me as that much different than Neptune and Uranus’ romance?
    I wonder if people are so quick to dismiss the romantic angle in this case because it makes more “sense” for them to be sisters given their similar designs, but also because they’re both pretty “femme”. With Haruka and Michiru “normal” gender roles are pretty heavily at play until their reveal as senshi (BRING BACK URANUS’ CAPE), and even after that they fall pretty squarely into the butch/femme dynamic, and of course there’s so much time to grow to love them together.
    As for Ms. Takeuchi’s (forgive me if I misspelled her name) intent, knowing her penchant for vagaries and conflicting details I feel that just the word “twins” underneath an illustration of the characters doesn’t necessarily mean that she literally meant for them to be blood sisters, maybe it’s more of just an extended metaphor for their bond as sailor soldiers of two stars representing one planet. Honestly though, characters being related by blood has never stopped Takeuchi from taking an overtly romantic direction (I’m giving YOU the side eye, Chibiusa/Black Lady). So really, who knows?

  5. I’m really glad you cleared this up for me! I really enjoyed Lethe and Mnemosyne in the manga as was curious as to what their relationship was.

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