it was stated in anime (i think at the ep with the kyubi) and in the manga (chap 94) that the third is the strongest of all and was called the 'professor'...

i know it doesn't sound immpresive, and you might think he came from Sliders of Futurama ("a succsessor to the professor?" Zoidberg, 'a clone of my own&#39, but it probably means he can kick serious ass...

EDIT: wrote 4th instead of 3rd, sorry bout that!