They include a theory which regards Ojin to be actual because his Japanese-style posthumous name, 'Homuda,' is extremely different from the embellished ones of the Emperors before the eighth, a theory which postulates that he is the founder of the conquering dynasty in the rotation theory of three dynasties, a theory to regard him as the god (Usa Hachiman) enshrined as an ancestor of the Imperial Family in relation to relocation of the Yamatai-Koku Kingdom to the east, a theory to regard him as the founder of the Kawachi dynasty, etc.
応神の和風諡号である「ホムダ」は飾りの多い8代以前の天皇と著しく違っている事から実在とみなす説、三王朝交代説における征服王朝の創始者とする説、邪馬台国東遷説にまつわり皇室の先祖として祭られている神（宇佐八幡）とする説、河内王朝の始祖と見なす説などである。