Jealous Younger Sibling
A (mostly female) younger sibling leery of anyone his or her sibling tries to date.
My Sister Is Off-Limits! is when a relative has veto power over a relationship with a friend of theirs. Big Brother Attraction and Father, I Want to Marry My Brother is when a young girl confuses romantic attraction and familial love, to different degrees. This is a trope for younger (particularly female) siblings, who tend to have less veto power than their older siblings who may not have any desire to have a romantic relationship with their older siblings, but still act like a Clingy Jealous Girl whenever their sibling does try to get into a romantic relationship with anyone. Compare Big Brother Worship and Big Brother Attraction.
Examples:Anime and Manga
- Kobato Hasegawa from Bokuwa Tomodachiga Sukunai is very clingy and jealous when someone makes a move on her older brother Kodaka.
- Shizuru in Candy Boy is very jealous of her older sister Kanade's relationship with Yukino--who is also her older sister.
- In Revolutionary Girl Utena, Nanami lets everybody know that her big brother Touga is the best. She is so obsessed with being onii-sama's sole target of attention that she got rid of his kitten and humiliates a girl from her Girl Posse. After realizing what a Manipulative Bastard her brother is, we see how her hopeless devotion to him is actually quite tragic.
- In the Mai-Otome manga, where Alyssa tries to replace the Otome system with copies of Miyu, which would dramatically alter the military and political landscape of the entire world... so her beloved big sis Natsuki can quit her job as Headmistress of the Otome academy and thus have more free time to spend with her.
- In Degrassi Takes Manhattan there is a rivalry between Holly J. and Fiona for the affections of Declan who is Fiona's twin brother and Holly J.'s boyfriend. Fiona's attitude is "Boyfriends are temporary. Brothers are forever." She has an emotional dependency on Declan and couldn't stand to come second in his life which she makes clear to a whole party of people.
- In "Twilight of the golden witch" from Umineko no Naku Koro ni, six-year old Ange takes an immediate dislike of Beatrice, not completely because she's the witch who killed her family (the six-year old version, when in control, isn't really aware of that), but more out of jealousy, which Beatrice notes and teases Battler for not realizing.
- In My Little Pony: Friendship Is Magic, everypony assumes this of Twilight when she becomes suspicious of Cadence marrying her BBBBF Shining Armour. However, she was right in being suspicious, as 'Cadence' was really Queen Chrysalis, who was using Shining Armour as a food source.
- On Phineas and Ferb there's Susie to her older brother Jeremy. If nothing else she seems to fit the "doesn't want to lose him" model, as she's fiercely jealous of Candace becoming his new "favorite girl."
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