Kyouya: From a club standpoint, I guess I am...
Usually appears in the Harem Genre, and keeps a look out for the major, non-daily disturbances in the household. Outside of that, the cast is on their own. This character is collected and cool as a cucumber, and isn't about to stress about every little thing. They have more fun amusing themselves with the cast's antics.
Notable for being probably the only character who will give you a simple straight answer for anything.
Usually older than the rest of the cast and (almost) never a romantic possibility (though occasional flirting isn't ruled out). Frequently has a sneaky streak that is not initially obvious and is thus an Unflappable Guardian.
- Tsubame Ameyagi in Ai Kora is an interesting case. From the girls' perspective, she's the harem nanny — but to Hachibei, who's only interested in individual body parts, she and her legs are definitely part of the harem.
- Miyabi in Ai Yori Aoshi is Aoi's caretaker and the house manager. When the Supporting Harem begins moving in, she takes it upon herself to supervise them. Despite her initial disapproval of Aoi's relationship with Kaoru, she later becomes their biggest supporter.
- Shigure in Fruits Basket. Except for the straight answer part. Hatori and Hatsuharu fit also, since their main role in the story is keeping the others in line.
- Maria in Hayate the Combat Butler will occasionally have this role, depending on the episode. Granted, other times she's just another member of the harem, but otherwise she embodies the trope fairly straight.
- Haruka in Love Hina. While Keitaro is officially the landlord at Hinata House, she's the eldest and the one generally responsible for wrangling everyone, particularly when a crisis mounts.
- Chizuru, as well as most older characters in Negima! Magister Negi Magi (Albireo, Takemichi, Konoemon, ect.)
- Subverted in the case of Takamichi, as while he would otherwise be a straight Harem Nanny, the heroine has a hard crush on him. This is revealed to be more than just for laughs, as he reveals an angstier side of him when he rejects her advances, commenting that he is not worthy of being loved.
- Kyoya of Ouran High School Host Club isn't the president of the club, but is considered the "mommy" of the group. Then again, he could just be considered a pimp. He is the one with all the answers as to what is going on, since Tamaki was too busy with ladies.
- Nekonome-sensei fills this role in Rosario + Vampire, as she's both Tsukune's homeroom teacher and the sponsor of the Newspaper Club.
- Her rather playful personality (while appropriate enough for a Cat Girl) couldn't exactly be described as "cool as a cucumber", though.
- Miya in Sekirei, she is older than the rest of the cast and seem to enjoy teasing the protagonist calling him "Criminal". Being in charge of the main cast's residence and their food supply, as well as being a Sekirei herself who can basically beat anyone in the cast up to an inch of their lives, she basically keeps the entire cast celibate and under some level of control by her force alone. She has her reasons and when those are resolved and the series ends she lets up on a few of the rules.
- Tenchi's grandfather Yosho in Tenchi Muyo!.
- Though he most definitely would not give Tenchi a straight answer. And then third OVA introduced a whole bunch of these characters (Seto and Airi at the very least).
- The School Nurse Mikado in To Love Ru is pretty much the only somewhat sane female character next to Mikan. She does have her moments though.
- A couple different characters play the role at different times in UFO Princess Valkyrie. Usually it's Kazuto, though occasionally Rika and Akina play the role as well.
- BC in Vandread - a no-nonsense second in command of the space pirate crew composing most of the cast and one of the few females to not overreact to having males stuck with their Amazon Brigade. Mainly because he's a Double Agent. Yes, "he".
- Fate/Harem Antics: Taiga always did her best to help Shirou and keep his admirers (who he never noticed) under control. Once the Holy Grail War started, however, she was Locked Out of the Loop and mostly too confused to help. Iri makes her the Master of Ruler so that she can stay involved, giving her the official duty of looking after everyone, and hopefully join Shirou's harem. An omake chapter set after the main story reveals that she did eventually join Shirou's harem.
- Gabriel serves this purpose in Marriage of Heaven and Hell, who lets the Occult Research Club stay in her house, acting as the official Shipper on Deck so that her son Makoto can finally find a girlfriend.
- The Young Riders has Emma, the Pony Express station 'housemother' is pretty much this to the Pony Express riders. And she's handy with a shotgun, too, when outlaws coming calling.
- Reine in Date A Live. While everyone in the organisation of Ratatoskr supports Shidou in his role of dating the Spirits, Reine appears more frequently than most and has the most serious personality (though even she has her Cloudcuckoolander moments). The light novels reveal the reason for her behaviour: she's actually one aspect of the Big Bad and Shidou making the Spirits fall in love with him is a core part of her plan.
- Chifuyu Orimura from Infinite Stratos is this for her little brother Ichika's ever-growing harem. She's also his homeroom teacher, dorm monitor, combat instructor, and did we mention she's also the strongest IS pilot? It doesn't help that she essentially took care of him while growing up so his world revolves around her to a degree. In the eyes of the harem, rather than being the Nanny, she's the Final Boss (especially for Laura, as Chifuyu is her commanding officer)
- Anne the Lady-In-Waiting in My Next Life as a Villainess: All Routes Lead to Doom! watches with bemusement and a certain amount of cringing as numerous boys and a few girls all fall for her tomboyish and rather dim charge, who never notices a thing. She pretends not to understand why Katarina is so popular, but she admits to herself that she knows perfectly well why. She would probably die for Katarina herself even if she isn't part of the ever-widening harem.
- Yoriko from Nyaruko: Crawling with Love!, who for added fun is also the mother of Mahiro, the central figure of the story's Love Dodecahedron. Thus the "nanny" aspect mainly comes about through her gentle but firm Mama Bear attitude towards "Hiro-kun's" pursuers, though she is actually fond of the aliens living under her roof and even seems to be playing matchmaker for Mahiro and Nyarko.
- Tomoe Nanjou in Tsuki Tsuki! usually has to take care of her son's harem. Bonus points for at least half of the harem living in her house.
- Fujimura Taiga in Fate/stay night is a partial fit for Harem Nanny. She's definitely not cool as a cucumber (in fact, she's the main comic relief), but she's the gatekeeper of Shirou's harem; each time another girl invades his house, Shirou's first problem is how to explain it to Taiga.
- The main ones in Sakura Wars are the Fujieda sisters Ayame and Kaede (but not at the same time; Kaede is the convenient substitute when Ayame becomes unavailable from Sakura Wars 2 onward), with the Grand-Mère taking this role in the third game. Ratchet Altair carries the torch in Sakura Wars: So Long, My Love, though the trope can be subverted on a New Game Plus if the player chooses to romance her.