my speculation at the end of the manga
1. Naruto < the SHOW
2. Minato < because it was said that only naruto can surpass his father
3. Tobi < coz only naruto can beat tobi if naruto manage to control the kyubis power. tobi would be number 1 if he got the fox
4. sasuke < narutos rival, with the power of itachi
5. sarutobi prime < . stated that he WAS the strongest kage, but why i put minato ahead of him? coz he WAS thats why he said to iruka dont used past tense. minato surpass him
6. edo madara< i dont know if i should put him above hiruzen
7. edo nagato < nagato is powerfull but edo madara beats him. he is not kabutos trump card that says it all.
8. edo itachi. < he become number 8 closed to nagato coz he is a edo other wise he would be drop to a lower tier coz of his sickness.
9. hashirama. hype
10. madara almost equal to hashirama
11. tobirama i dont know if i should put tobirama above hashirama( lets me just put him here)
12. PAIN (nagato)
13. jiraiya by hype itachi said all he can do is a stalemate with kisame. nagato also said he can beat him if he jiraiya knew his secret.
13 itachi. he is powerful and intelligent but lacks stamina.
14. kabuto no edos, if we count his edo he should be talking the spot of edo madara.
15. 3rd raikage.
i dont put 6oSP and his two sons.