As there is no record of Shikeshimaro found, it is assumed that he died in Tosa Province, but Kawatsugu, supposed to be his brother, appeared in the historical book as if replacing Shikeshimaro, so that some theories claim that the two of them were the same person.
志計志麻呂の記録はなく、土佐で死去したと思われるが、弟とされる川継が入れ替わるように史書に登場するため、両者を同一人物とする説もある。