Judging from the name, there is also a theory that claims Soganoishikawa no Sukune who was thought to be the founder of the Soga clan to be a fictitious person created by Ishikawamaro or his descendants.
蘇我氏の祖とされる蘇我石川宿禰は名前から見て、石川麻呂もしくはその子孫が創作した架空の人物であるとする説もある。