Collateral evidences for that include: a fact that his name is fundamentally different from those of Richu and Hanzei which bear the title of wake (which means 'coming into being'); a legend that he was despised by these two Emperors as a fool because of his illness and his accession to the throne did not proceed smoothly; a story told in genealogies of Soga and Katsuragi clans which were the influential Gozoku of the time that there was reportedly a person known as WAKUGO no Sukune who was a son of TAKENOUCHI no Sukune at a period which overlaps that of Ingyo; and a problem in the "So-jo" (the Book of Song) that it does not describe any blood relationship between King Sai of Wa (Ingyo) and King Chin of Wa (identified with Hanzei).
その傍証として、ワケ号を負う履中・反正とは根本的に異質な名であることや、この2天皇から病気を理由に愚か者として軽蔑されていて、即位が円滑に行われなかったという所伝、当時の有力豪族たる蘇我・葛城氏の系譜に、武内宿禰の子として若子宿禰という人物の存在が伝えられ、時代が重なること、さらには、倭王済（允恭）と倭王珍（反正に比定される）の血縁関係を記さない『宋書』の問題などが挙げられる。