Tags: Manga.
Spiral: The Bonds of Reasoning (スパイラル〜推理の絆 Spiral: Suiri no Kizuna) is a fifteen-volume shōnen mystery manga series written by Kyou Shirodaira and illustrated by Eita Mizuno. It was published by Enix and then Square Enix in Monthly Shōnen Gangan from February 2000 to October 2005 and collected in 15 bound volumes. The series focuses on Ayumu Narumi and his efforts to solve the mystery of the Blade Children cursed geniuses with cat-like eyes lacking a seventh rib bone.