Board Thread:Theories and Speculation/@comment-26636534-20150710195521/@comment-734582-20150712140122

Chaosattractor wrote: People can and do get killed before they can pull out their last lines of defence, you know. That applies to the attacker too.

Itachi (without disease) is clearly up there as a post-kage level Ninja, he would be nigh-invincible. I do think Rinnegan is inherently stronger because it gives more powers and a greater variety of abilities to deal with enemies. Some of the most powerful ninja (e.g. Hashirama, Madara) are stronger than him, and the Third Hokage may be equal or above him.

Note that if the amount of enemies that may defeat you is limited to handfuls in a world with ~100 000 ninja i'm sure the moniker "nigh invincible" is justified.