* AlternativeCharacterInterpretation: What exactly is the deal with the Maou? Is he a separate person who happens to share Yuuri's body a la ''Anime/YuGiOh''? Is he the personification of Yuuri's darker side? Does Yuuri just have a [[SplitPersonality dissociative personality disorder]]? No-one really knows.
* AmericansHateTingle: Hate isn't the right word, but Conrad is considered boring to many Western fans for being the "perfect guy who completely understands Yuuri". It's this dedication that is rather fatherly that turns people off (when it comes to pairings, as Conrad/Yuuri is significantly more popular with Japanese fans than Western ones).
* {{Anvilicious}}: The writing isn't exactly subtle when conveying the important themes of this show, what with Yuuri's constant monologues about how love is always the answer and you have to love everybody everywhere and never stop, ever! Although between Yuuri maturing into this role (which is honestly more about 'understanding and accepting everybody' than 'loving' them, although his vocabulary is noticeably influenced by his mother), the fact that the narrative allows many dissidents to be rounded characters who have good points counterbalances this rather. We are not forced to believe Gwendal is being unreasonable in preparing for war all the time, or that Conrad's willingness to sacrifice anything and anyone for Yuuri is not a potentially valid alternate morality.
* BadassDecay: Saralegui starts off as cool and diabolical, and by the end of the series is... a little childish.
** [[FridgeBrilliance But when you think about it,]] he was a child all along. Since he was [[spoiler: [[ParentalAbandonment abandoned by his mother]] and [[AbusiveParents ignored by his father,]]]] he probably felt alone and came up with his scheme to interact with people in the only way he knew how. In order words, he [[spoiler: tried to take over Yuuri's body and rule over everything]] because he wanted to be loved.
* CreatorsPet: Saralegui is accused of being one especially by the shippers given that he's introduced in season 3 and takes the spotlight away from Yuuri's other companions as well as being set up with the most {{Ship Tease}} in that season despite the development that happened in the previous two seasons.
* DieForOurShip:
** Not as frequent as other fandoms but Saralegui gets a lot of flak from any other person that prefers Yuuri with someone else (mainly Yuuri/Wolfram fans). After all his previously built-up relationships with other guys never cracking his TransparentCloset, Yuuri suddenly crushes on Sara for shallow reasons.
** Conrad also frequently gets the RonTheDeathEater treatment from the more militant Yuuri/Wolfram fans.
** The reverse is also true in Conrad/Yuuri fanfiction. Either that, or Wolfram gets over his feelings far too easily for a [[ClingyJealousGirl Clingy Jealous Guy]] with a HairTriggerTemper.
* EpilepticTrees: Mazoku aging; HOW DOES IT WORK!? Just take a look see at the entry for YoungerThanTheyLook. The Headscratchers page is as of now completely devoted to the question.
* FanPreferredCouple:
** In the Western fandom, [[BelligerentSexualTension Yuuri/Wolfram]], [[HeterosexualLifePartners Conrad/Yozak]], [[PairtheSpares Gwendal/Gunther]] and [[spoiler: [[SubordinateExcuse Shinou/Murata]]]]. In the Eastern fandom [[KissKissSlap Yozak/Murata]] is an unusually popular pairing.
** Conrad/Yuuri seems to be a favorite ship among American fans, to the extent that for many years, the rare few excerpts that were translated from the novels were of the Conrad/Yuuri variety, such as the coffin scene in the Seisakoku Arc.
* FauxSymbolism: [[spoiler: The keys to the boxes are]] [[TheLancer Conrad's arm]], [[TheSpymaster Gwendal's eye]], [[LoveInterest Wolfram's]] [[UndyingLoyalty heart]], and [[TheHero Yuuri's]] [[TheHeart soul]].
* GeniusBonus: The uniforms of Conrad, Wolfram, and Gwendal. Few people would know that they are patterned on real historical uniforms.
* MentorShip: Conrad and Yuuri are actually the most popular ship in Japan. Wolfram beat Conrad out in America, probably a case of ValuesDissonance.
* MoralEventHorizon: King Belar has already crosses this in his backstory when he kills [[spoiler: the previous owner of one of the four keys in order to activate the boxes.]] It gets worse from there.
* NightmareFuel: The gremlin-style Bearbees.
* TheScrappy: Saralegui is not well liked in the fandom for many reasons.
** 1. He starts out as a pretty good villain (or at least {{Anti Villain}}) but goes through {{Badass Decay}} to the point that people thought his character was wasted.
** 2. His [[DudeLooksLikeaLady character design]] turns a lot of people off especially since Yuuri who has been claiming to like girls the entire series suddenly develops a crush on him if only because of his feminine appearance, which makes Yuuri look shallow.
** 3. He gets in the way of ''all'' the pairings involving Yuuri. Especially jarring because he's introduced in season 3 and gets the most {{Ship Tease}} with Yuuri effectively pushing the other characters like Wolfram or Conrad out of the picture making shippers declare that he's a {{Creators Pet}}.
* SeasonalRot: The third season was met with a pretty lukewarm fan reception, compared to the first two.
* ShipToShipCombat: Several, but Yuuri/Wolfram vs. Conrad/Yuuri is probably the biggest one. Or Yuuri/Wolfram vs. ''any'' other Yuuri pairing, as is often the case in the English-language fandom.
* ThisIsYourPremiseOnDrugs: Take ''Manga/FushigiYuugi'' and combine with HoYay and [[ThisIsYourPremiseOnDrugs a good amount of acid]].
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