Itachi, is currently. Whether they're dead or alive the strongest.
One he lied when he compared his strength to Jiraiyas.
Why!? He honestly didn't want to take Naruto. If he did Naruto would of been long gone. We all know this. His whole approach was shady. It was exactly what tobi said, he was only there to remind Danzo to not touch sasuke. If you pay attention to how he's talking to Jiraiya you can see how much information about akatsuki he's actually giving him.
Itachi easily could of killed Jiraiya, next up Nagato.
Nagato is a hard one to judge. Regardless of his Rinnegan abilities he's actually fairly weak. His combination of abilities promote a long range fighter but yet he fights hand to hand. Based on pure Ninja intellect Itachi wins this battle. Also we all know Nagato is prone to Genjutsu.
Obito knew itachi was stronger, the one thing that kept him alive was Itachi's belief that he in fact was Madara Uchiha. Obito is weak and has proven to me it is in fact Obito his mistakes, reliance on that one Jutsu and Ninja tools is more then enought proof. He reserves too much chakra and I honestly think Obito knew he couldn't even begin to fight Itachi. I honestly believe that if Itachi was allowed to live an uninterrupted life in Konoha, he would of been the 5th easily. Everything this man did had purpose. He told sasuke how to obtain the Mangekyo then the Eternal all by acting out a role masking the true intent of his words. He wanted sasuke to know the truth, thats why he kept asking him how much can you see, but sasuke is retarded.
Kakashi, why did I just waste time writing this....
Madara Uchiha(No Hashirama DNA OR Edo) age 30 versus Itachi Uchiha age 30
From what we know Madara is showy he likes flash, bang boom. HE"S DEAD...
here's why, only one person is on par with Itachi's genjutsu effects and thats Naruto's tricks. Turning clones into rubble to finish the last pain, digging tooth and nail to finish Neji in the Chuunin exams. Not to mention how HAM (HARD AZZA M_____R) he's going now. I just dont see any person running up on Itachi getting very far. Regular Madara against his age Itachi is getting flatlined. You dont think so tell me why? EMS? bullshit, Tie at best for Madara, if he makes it past the first genjutsu with his powerful chakra he wont get past amaterasu instantly after while he stumbles from never being hit by such a powerful genjutsu.
I'm just going to make a list of all Characters that flatline to Itachi's Genjutsu
Minato, Itachi's current age (S difficulty) same age (Like goku asking Krillin to block Kamehameha for him)
Hiruzen (Old, Dead in 5mins) (Young, Owns Itachi and the Whole Ninja world 1on1)
Hashirama (Dead, Tsukuyomi)
Tobirama (Dead, Tsukuyomi)
Sasuke (Real Intent Dead, .01secs)
Naruto (Dead, naruto couldn't fight one on one and not make a mistake and thats all it takes with Itachi.)Genjutsu won't work, but Itachi's shuriken will. Plus we dont know if he could control the fox. He had no intention.
Killer Bee (Itachi's toughest fight, like I said with Intent I think he could control the beast) You say how can they control it inside its Jinchuuriki? I say, ask Sasuke. He already did it.
And I'm done.
hiruzen dies any age
hashirama win via bringer of darkness