Who is the Strongest Ninja in Naruto?

Who is the strongest Ninja in naruto? I personally think its Rikodou Sennin because he is a ninja God and he helped Minato (4th hokage) defeat the 9 tailed fox that Rikodou's Brother created before Rikodou banished him to the otherworld along with his "children" the tailed beasts Rikodou has all Kekkai Genkai and took the forms of the Six paths of Pain and is now in form of Tsunade (As Tsunade revealed in one of the Naruto movies) Rikodou is Legendary but was almost killed seeing as how Pain almost killed Tsunade (Rikodou Sennin). But is there a stronger ninja out there. Rikodou failed to seal the 9 tails fox, and instead Minato sealed it inside of Naruto, Rikodou was almost killed in the 9 tails attack and seeing as how its in Naruto, if naruto can take the full form he could be stronger then Rikodou. Pain possess the Rinnengan, and destroyed the Leaf during Pains attack, however Madara is the strongest Uchiha and has the strongest Sharingan in the Uchiha Clan, so Rikodou probably isnt the strongest but im not sure who is the strongest. What's your opinion on who is the strongest ninja in naruto?