Sensei

[Chīkara]

orichimaru-sensei

 

[know it all]

The Senju brothers. If you go down their line they have the most powerful shinobi tree.

yah, all the freakin way from Hashirama to Naruto to Konohamaru

 

[kourosh]

jiraiya or kakashi

 

[Fusion Reborn]

Kiritsugu..

 

[startup97]

Guy and Hiruzen

 

[The Immortal God]

I would have to say J-man or Gai