These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Alternate Character Interpretation / Base Breaker: Nina Wang: Girl who always did her best only to get manipulated by Nagi and Sergay, tragic figure who has good intentions but started down a dark road due to a few critical mistakes, or completely and utterly amoral individual who is willing to commit mass murder for the sake of her incestuous love for Sergay?
Big Lipped Alligator Moment: Shiho's dream sequence in episode 21. Made even more disconcerting by the fact it pops up in an otherwise tragic episode.
Complete Monster: This anime has Tomoe Marguerite, a Psycho Lesbian to the extreme.She's a Bitch in Sheep's Clothing that uses her charm to mask her malicious intentions, and almost everyone fell for it. Throughout the show, she tried to personally take out Arika, because she saw her as a potential threat to her affections towards her elder Shizuru Fujino. Her most despicable act involved her trying to convince a gang to rape Arika, knowing that if they went through with it, her Otome powers would be neutralized. She later went on to betray the Alliance, stating that she deserved to have anything she wanted, and that everyone's lives (except that of Shizuru's, of course) were meaningless to her. Not even her supposed love for Shizuru is a redeeming factor, since she essentially made her into her plaything and took great pleasure in it. When Shizuru had revealed to her that she never loved her, Tomoe rants noting the similarities between her and the older Otome, and states that she was entitled to be the only person to have her. She then attempts to attack her and Natsuki.
Die for Our Ship: Mahya. This is more understandable than many examples, as she deliberately interferes with Akane and Kazuya's attempts to have sex (instead of merely being someone either one could be or is interested in), but she still gets a lot of hate for interfering with the couple.
Draco in Leather Pants: Nina. Despite her detractors, she still has fans willing to overlook or excuse her actions in later episodes.
Ensemble Darkhorse: Erstin's unexpected popularity among fans of the anime led to her surviving in the manga continuity, and actually being a member of the main Power Trio.
Jerkass Woobie: Mimi is not the most pleasant individual, especially considering that she's willing to let Aoi die for her loyalty to the queen], but her backstory (her father losing his job, becoming an alcoholic and dying) and her own eventual death are quite tragic.
Fanon Discontinuity: Those who take the series seriously tend to ignore what little "plot" there is in Mai-Otome Zwei as much as possible, and advise others to do the same.
Arika and Mashiro have a bunch of moments together in the later episodes that border on romance scenes where they encourage each other to keep going.
Erstin with Arika and Nina, particularly Nina. In one scene in the pool, when a water monster slithers by her, she assumes Nina is feeling her up, but bashfully tells her that If It's You, It's Okay. She also sends Nina and Arika a letter saying that eve though she was told not to make any friends at the school because she was a Schwarz infiltrator, she still found herself becoming close to them.
Aoi and Chie. When Nao asks why Chie was in town the same night she captured some thugs who were attempting to rape Arika, Chie jokingly replies that she had "a date." After Aoi almost dies performing her Heroic Sacrifice for Mashiro, Chie visits her in in the room where she is being treated, and is overjoyed when she regains consciousness.
Usually happens when Erstin or Natsuki is involved.
Magnificent Bastard: Nagi. It's hard to tell exactly when he started plotting, but in the end he was able to Gain control of the entirety of Windbloom, and is even able to gain control of the world breaking device through manipulating Nina and her affection for Sergay. Hell, through Schwartz's assistance, he was even able to make a new brand of Otome.
Moral Event Horizon: For Nagi, the point where he shoots Sergey and then ties him to the Harmonium, and then forces Nina to run it to keep him alive. For Tomoe, her organization of the Attempted Rape scenario, which thankfully failed.
Unpopular Popular Character: Shiho is considerably better liked by the fans than her HiME counterpart, but itís revealed in the sound dramas that she is by far the least popular Otome among those that Backstage sells merchandise for, especially after her fairly humiliating outcome from the incident in the pool (which was mostly her fault).
Viewer Gender Confusion: Gal is female, but given that she's a Cyborg and her voice is distorted, it's hard to tell.
Villain Decay: Despite often proving a threat to Arika's Otome career and life, in Zwei, Tomoe shows up as Ishigamin's running mate and supposed girlfriend, and is dismissed as an annoyance. Ishigami also gets this, as his Mai Hi ME incarnation was essentially responsible for setting the bloodshed of the last 10 episodes in motion, while in Zwei, the citizens mock his attempt to run against Yukino.
The Woobie: Erstin. She was becoming friends with Arika and Nina despite trying to avoid becoming attached to anyone at the academy, but knew the "black letter" from Schwarz would come one day and she would become their enemy.
Evil Is Sexy: In the manga, Fumi, after being turned and Dark Hime!Yukariko.
Idiot Plot: The Arashi plot can basically be summarized as "Garderobe is bought by a crooked noble and the Otome turned into Go Go dancers, but no one seems to think that the most powerful institute in the world needs to be rescued." Yeah.
Gets even worse near the end, when we are forcibly reminded that many of the Otome have some very wealthy, powerful relatives (They are eventually saved by Natsuki's mother. You know, the one who owns a country?!) who could have resolved the entire situation in ten minutes, yet nobody ever asked them for help.
Natsuki argues that Garderobe, an international organization, can't have deep ties with a single country, but her mother disagrees.
This goes double for the Super-H extra which came with Arashi, which basically boiled down to justification for fanservice.
Moral Event Horizon: Most of Sergay's actions after his being revealed as evil qualify, including killing Mashiro when she is no longer useful, trying to destroy the world and almost killing Manshiro.