Nerd.
That had been Chikaze Asada's label since she was a child. Even as a kid she was fascinated with art, anime, and reading. While other kids played and laughed together, she taught herself martial arts from manga and TaeKwonDo for Dummies. While other children watched cartoons or movies, she was absorbed in anime. While other children went to the park or out with friends, she drew alone, at home in a corner.
Her nerdy self was a counterpoint to her perfect twin, Hikari. Her twin was the image of a flawless child. She was girly, attentive to her studies, never talked back, was cool, pretty, and smart, and did everything she was told. People would always tell Asada to "Be more like your sister!". But she couldn't.
Her parents doted on Hikari, seemingly ignoring Asada. She got used to it, and became an introvert. Eventually though, it was too much when her parents barely remembered to feed her, and she wished she could be somewhere else...
Her wish was granted...by a demon. And she was transported to her favorite anime, Akatsuki No Yona.
Transmigrated into DxD World-Kuoh Town, Hibari Kyoya. an average student, spent 18 agonizing years in the world fully aware of the dangers, knowing he is utterly powerless in a world of gods and monsters, Until...
[Ding! Sign-In System loading... 20%... 50%... 80%... 100%.]
Destiny, it seems.. has a cruel sense of humor. A [Sign-In System], long overdue, finally bursts to life within him, offering a chance at survival, a chance at power...
[Ding! Congratulations! You have received the Rainbow-Grade Gift Bag!]
...
He then started completing System's tasks, accumulating even greater rewards.
[Ding! Task completed. Reward: Perfect Rumble-Rumble Fruit (Weakness to water Removed).]
[Ding! Task completed. Congratulations to the host for obtaining the Flying Thunder God Technique!]