He is said to be the oldest okimi (Emperor), actuality of whose existence is high, but, because descriptions about him overlap and are confused with a paragraph on Emperor Nintoku, there are theories presented including one that Ojin and Nintoku are the same person.
実在性が濃厚な最古の大王（天皇）とも言われるが、仁徳天皇の条と記載の重複・混乱が見られることなどから、応神・仁徳同一説などが出されている。