Everyone's inner thoughts are disguised monsters (Hollow/Huoluo).
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Nishizawa Kayuko always thought she and Tsuna and the others were good friends. She never expected that, after an accidental kidnapping, she'd gain the ability to hear people's inner thoughts.
As it turned out, she was the illegitimate daughter of a certain Italian mafia family. Their friendship had only been an act, meant to put on a show for her nominal father so the Vongola family could swallow up that family.
On the last day to submit her school application, Kayuko changed her choices without hesitation. After that, she lost contact with everyone involved in their mafia pretend-play game.
After Kayuko left, they were consumed with regret over how they'd hurt her and driven her to leave in silence.
Kayuko: ?
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When Kayuko moved on to middle school, she was ready to get along with her new classmates at the technical college, but all she heard were thoughts about how much they hated her. As it turned out, her maternal relatives were a bunch of rotten old traditionalists.
Unwanted Kayuko chose to ignore her three classmates and go it alone.
In her second year of high school, she nearly died. Without a second thought, Kayuko transferred schools. After she left, even her homeroom teacher, Yaga, couldn't get in touch with her.
The young sorcerers grew more and more miserable. The people she'd saved had ended up hurting the person who mattered most to them with their own hands.
Kayuko: ??
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On her first day after transferring, she ran into two delinquents fighting. The two boys soon became friends, but they also kidnapped Kayuko in the process.
She thought she'd been hated again and was about to get beaten up by the delinquents. But it turned out the other guy was just a chuunibyou in the terminal stages, one who hated everyone equally.
Get a grip! You're already in middle school!!
Kayuko thought she'd found a relatively normal middle school life, only to be kidnapped by two of her classmates, who said they wanted to take her along to fight evil vampires??
Kayuko: What are you talking about???
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After saving the world, Kayuko disappeared. She was swept up in a war that belonged to the night.
Kayuko was a mage who hunted monsters beneath the neon lights of the city. Though she'd lost both legs, she remained a Ring Sorcerer with tremendous power.
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* The heroine is beautiful, strong, and tragic, and a fan favorite. She's easygoing and genuine: if someone likes her, she likes them back; if someone hates her, she doesn't care and simply avoids and ignores them. She's incredibly strong-willed.
* A Mary Sue, reverse-harem romance, full of melodrama and OOC. Everyone ends up in the doghouse.
Theme: Love yourself before you can love others.