As far the manga is right know, I would say Yes !With Rinnegan and EMS does that make Madara the strongest ninja ever? Besides SO6P of course.
That was before his Rinnegan.No, he is not. This so called strongest ninja besides the SO6P was beaten by Hashirama Senju, the first Hokage.
Edo Tensei is giving him more power boost than you think. Kabuto already explained that his Edo body is "special" compared to the rest, making him much stronger than he was in his prime. Without the Edo, there would be no prime Madara. He wouldn't be able to use his meteor attacks either unless he had a deathwish.That was before his Rinnegan.
Now he has:
EMS
Rinnegan
Mokuton Release
Great chakra and overall fighting skill/experience
And one more thing, even if he were to die, he would just need to cast Izanagi and could fight on at full health/chakra with his other eye left. And since Rinnegan does not require both eyes for the techniques he would not loose too much fighting power. Plus a few minutes complete immortality from the Izanagi itself.
Now thats what you can call OP![]()