As it is described that it was an achievement made by Sahei Fukushin, it could be thought that he was a close blood relative of Fukushin KISHITSU, who worked hard to revive Baekje and died in 663, two years before Shushi KISHITSU received the status, but the relation between them is still unknown in detail.
佐平福信の功によって、とあるため、百済復興に努めて2年前に死んだ鬼室福信の近親者と思われるが、具体的な関係は不明である。