The most powerfull living character in naruto has to be
-Madara uchiha...ony if he gets his powers back..but hes basically just a apparation rt now,kinda like voldemort in hp-1 -Then its a close one b/w Naruto n Sasuke..sage mode vs the susanoo.. -U can also add the hokages in no particular order.. -A mention about Hisame..with the chakra eating sword..
FRom the deseased ones. -The sage of 6 paths obviously 1st.. -Minato for sealing the 9 tails..+ the 1st Hokage for defeating uchiha
-Pain for using all 6 jutsus... -Itachi ..maybe the most complete sharingan user.. -Then the rest..
Probably lee, he proves this when he defeats Mara(Or whatever his name is, the sand guy)in the tounament, when he opens all the gates.