Fujiwara no Yorinobu appears as a historical noble figure. He is linked to the Minamoto clan through his father, Minamoto no Mitsunaka (Tada no Shinbochi). Political machinations by Fujiwara no Michinaga, seeking control of the "golden armor," compelled Shinbochi into a marriage with the sister of Fujiwara no Yasumasa. This union led to the exile of Shinbochi and Minamoto no Raikou's mother, Tamagushi, from the Heian capital. They faced attacks by Horrors until rescued by Abe no Seimei and Sakata no Kintoki.

Yorinobu is Raikou's half-brother, sharing the same father through the politically arranged marriage. Despite the family fragmentation, Raikou holds no resentment towards Yorinobu and resolves to protect him. This underscores Yorinobu's role as an innocent figure within the conflict, whom Raikou values as family.

A sword fighter, Yorinobu wields a blade as befits his status and the martial setting. His background ties him to the political schemes of the Heian period and the Fujiwara clan's influence.