weaselflare
spartan
itachi. of course this is only a possiblility.
okay heres my reasoning. sai's eyes look like the uchihaa eyes without sharingan, and not every uchihaa has sharingan. the person in the book with no face looks like itachi without a face. sai could have been taken from birth, which would have been shortly before sasuke. because he didnt grow up with the uchihaas, he was never forced to learn fire, so instead he teaches himself the ink thing. since they were seperated when they were younger, sasuke wouldnt remember sai, so there wouldnt be any real reaction from him. plus sai and itachi have the same hair style lol
this is kinda far fetched but its the only lead i got
okay heres my reasoning. sai's eyes look like the uchihaa eyes without sharingan, and not every uchihaa has sharingan. the person in the book with no face looks like itachi without a face. sai could have been taken from birth, which would have been shortly before sasuke. because he didnt grow up with the uchihaas, he was never forced to learn fire, so instead he teaches himself the ink thing. since they were seperated when they were younger, sasuke wouldnt remember sai, so there wouldnt be any real reaction from him. plus sai and itachi have the same hair style lol
this is kinda far fetched but its the only lead i got