|“||...Thanks for the gun, I'll make use of it||”|
Seiji Harada (原田 静刃 Harada Seiji?) is the protagonist of Akamatsu Chūgaku's other novel Yagate Maken no Alicebell and a recurring character in the Hidan no Aria series. After failing his high entrance exams and escalated into Inou High, he came across Alicebell Tachibana Binyan whom their encounter changes his destiny.
In Volume 14, he and Alicebell duel against Aria and Kinji.
Harada wears dark clothing including black boots, black coat that covers his mouth, and two katanas on his back.
- He is Kinji Tohyama's counterpart in the Akamatsu Chūgaku's other novel, Hidan no Aria through the following similarities.
- Both have burdened pasts that holds back their hidden potential.
- Both are fighting prodigies with superhuman abilities.
- Proficient in both marksmanship and swordsmanship, earning the nickname "Quadra."
- Both can be victims of misfortune when dealing with their respective heroine partner's ferocious.