Mito han samurai. Kasuya was one of 24 members of Rôshigumi who decided to saty in Kyoto. But soon deserted and returned to Edo. He joined the Tengutô in 1864 and participated in the rebellion. But the rebellion was defeated and Kasuya commited suicide at Jihô-ji temple.
- Shinsengumi Zentaishi Tettei Guide (新選組全隊士徹底ガイド) Maeda Masaki
- J-Wikipedia Kasuya Shingoro