Among them, since YAMATO Takeru no Mikoto was sent to an expedition against Kumaso (a tribe living in the ancient Kyushu district), Iokiiribiko no miko was considered as a reserve in case something happened to Emperor Seimu.
そのうち日本武尊は熊襲征討に行かせたことから、彼は万一成務天皇に何かあった場合の予備だったらしい。