Hirayama joined the Roshigumi with Serizawa Kamo.
He was killed when Serizawa was assassinated at the Yagi residence.
References
- Shinsengumi Taishi Den (新選組隊士伝) Gakken
- Shinsengumi Zentaishi Tettei Guide (新選組全隊士徹底ガイド) Maeda Masaki
- J-Wikipedia Hirayama Goro