Late 18th Century France: a time of great trial and turmoil—and for none moreso than French Secret Police member d'Eon de Beaumont, whose older sister Lia has just been found floating in a coffin in the Seine River. Lia was an accomplished spy for the French Court, which recently sent her to faraway lands on a mysterious assignment. But now she's turned up murdered, and it's up to D'Eon to find her killers. No sooner has he stumbled upon the Ancient Conspiracy that might be responsible for it, than he, his comrades, and his entire household all fall victim to a vicious attack, which only D'Eon himself manages to survive. The King of France, Louis XV, graciously allows D'Eon to retrace his sister's steps and investigate her murder, and to that end he gives him a new set of comrades; all of them are Chevaliers who, like D'Eon, have vowed their unswerving loyalty to the King, even unto death.Of course...this isn't the only help D'Eon will receive during his investigations.It seems the angry soul of his murdered sister, Lia, has decided not to pass onto the next life just yet. She has some unfinished business to attend to. And she has found the perfect vessel through which she can carry out her revenge—D'Eon's own still-living body...Loosely inspired (very loosely) on the historical spy D'Eon de Beaumont, whose crossdressing (in retrospect, s/he was probably transgender, and s/he insisted for the latter half of his/her life that s/he had been a woman all along and had been disguised as a man previously) and extraordinarily half-hearted attempts at espionage caused a major international incident.The show itself is based on a series of novels by Tou Ubukata; a manga was released at around the same time as the show, but is completely different, being described by Ubukata as "a humorous attempt at combining d'Eon de Beaumont, eighteenth century France, and a superhero story". While the anime is a serious historical drama with mystical elements, the manga is a Seinen action series similar to Hellsing. Despite being a completely different animal, it's definitely worth a look.The show noticeably draws from the 1970's shojoanimeRose of Versailles.
Alternate History: An interesting example: instead of beginning from a point of divergence, it begins at a point that is in accordance with actual history, and slowly begins to diverge as the plot unfolds, and various historical figures meet very different fates than they did in real life.
It acknowledges this in the closing credits, where the dates of death are given for the real Madam De Pompadour and Queen Marie, who died two years apart. But in the series, they die on the same day.
The show cleverly uses this trope to fool the viewer into thinking that its version of Robespierre is part of the alternate history. In fact, the man who goes by that name for most of the series isn't the one we know from history; the "real" Robespierre doesn't reveal himself until the final episode, and things line up much closer to reality with him.
Break the Cutie: Robin is probably the happiest and most optimistic member of the main cast early in the series. By the end, however, he's become so angry and disillusioned he changes his name and becomes the historical Maximilien Robespierre, responsible for the Reign of Terror.
Brother-Sister Incest: D'Eon and Lia are close (uncomfortably close, now that they have to share the same body), but they've never felt anything improper towards each other. However, the relationship between half-siblings Lia and Maximilien Robespierre was almost consummated, although neither of them knew they were related to the other at the time of their romance.
First Episode Resurrection: An interesting variation; It's not his death and resurrection which gives D'Eon his powers, but his sister's. And it takes a traumatic event to "activate" them, as often befits this trope.
Flynning: Averted outside of staged fights, when two enemies are engaged in a fight, they go straight for the kill.
Gambit Pileup: It would be easier to list the characters who didn't have some grand scheme.
"The extras in the crowd scenes." Done!
Grand Theft Me: A slightly gentler form, where the soul "appropriating" a body shares it with its owner — although not always equally at all times.
Guile Hero: Durand, who fools both allies and enemies to accomplish his goals.
Hat Damage: Teillagory is very sad about his hat taking damage in battle. Except it's the only thing that's taken damage as his opponents all on the ground.
Hermetic Magic: The Functional Magic system used by the Ancient Conspiracy is a complex combination of Alchemy and Rune magic. It's practitioners are called "Poets" and the "spells" they chant are actually Psalms from the Bible. (A poet has to have their hearts "opened to the Psalms" in order to use them, though.)
Historical In-Joke: The entire series is one (albeit a very serious one) which details the behind-the-scenes events that lead up to the French Revolution and Catherine the Great's rise to power in Russia, amongst others. Many of the characters (including the hero) are actually based on real-life people from that era.
The thing about this show is that you're meant to take it seriously, but it does not take itself seriously. Which accounts for the immense historical inaccuracies.
Or rather, it takes itself seriously as an alternative history. It just doesn't seem like one at first.
Luke, I Am Your Father: Lia and Maximilien Robespierre aren't only half siblings, they're also the children of the last king, Louis XIV. And it turns out that Madame de Pompadour is the "mommy" of the skull that Queen Marie is always carrying around.
Smug Snake: The Duc D'Orleans is significantly less accomplished compared to most of the other villains, with the possible exception of Piotr and the Marquise De Pompadour
Spirit Advisor: The child's skull that Queen Marie carries around, dresses up, and speaks to all the time. Only near the end of the series do we learn of the child's true identity. The skull also pulls duty as a Waif Prophet, and were it still alive, it would probably be a Creepy Child as well.
Spoiler Opening: If you pay attention during the opening, you can clearly see that Teillagory is kneeling in front of the Philippe II, Duke of Orléans. Considering Philippe is portrayed as a villain, Teillagory turning out to be a mole is not very surprising at all.
However, you don't see the Duke's face, or anything but the very top of his head, making it near-impossible to determine who Teillagory is kneeling before, so it's easy to just write off the scene as being emblematic of his status as a loyal knight. Of course, once the revelation is made, it seems obvious.
Tap on the Head: Subverted in the scene where Robin tries to knock a guard unconscious with the butt of his pistol. He only succeeds in hurting the guard, and has to resort to a more vigorous attack to bring him down.
This is played with later on; it is revealed about halfway through the series that when two souls occupy the same body, they slowly lose their individuality. Sure enough, the differences between D'Eon and Lia become more and more subtle to the point that by the end of the series, the show no physical changes when they switch.