According to "Sangoku Buppo Denzu Engi", Eso was a scholar as well as a priest of the Sanron Sect (one of the Nanto Rokushu) and taught Buddhism to Prince Umayado.
『三國佛法傳通縁起』によれば、三論宗（南都六宗の一つ）の学僧で厩戸皇子の仏教の師となったという。