with no specifications?
thats very hard to pick one... I will dare to say fully SB Kakuzu..
If you want best blitz ninja then its Ronin Naruto
If you want best tankiness then its SB Kushina
If you want best defensive support then I will say edo Itachi
If you want best offensive support then I will go with edo Hiruzen
If you want ninja who can screw up any well buffed team and eventually you wanna troll your GNW teammates... 5k Madara is your answer.

But SB Kakuzu with 100 chakra is tanky, deals high damage and can serve as a solid support for other Akatsuki ninjas in both offensive and defensive way (removing debuffs, heals + giving extra standard attack). Given that, his ability to serve in multiple roles puts him on #1 spot for me.
*Given current available ninjas, upcoming ninjas and SB / ST will probably change it tho.

BEST NINJA IN ALL OF SHINOBI HISTORY IS HABUTO HOKAGE

BT bee tailed.

Hi,

imo, best carry are :

edo minato sb > Bee sb = kushina sb > kakuzu sb > ronin