Round 1: Reapers because the Kages don't impress me and neither should the shinobi alliance unless this includes Naruto, Bee, 8 Gates Guy (who would actually wreck Reapers)
Round 2: The Bijuu, they can spam nukes and all the Reapers have are big lasers
Round 3: Team 1 since they still have bijuu
Let see, the Reapers have a huge invasion force that take out all life in a Galaxy before. The Ninja army is basically not going to win this, the Reaper out number them a lot
edit: I didn't saw the limits LOL! Naurto might be able to take it then
@CerusSerenade: Reaper's at their biggest are two km's tall. I'm almost positive that the meteor is far larger than that, and hitting with a force that no Reaper can.
Actually i'm pretty sure the meteors were smaller than that. Just being one mile tall is massive.
@CerusSerenade: Actually it's pretty low if you think about it, it even said that in the wiki that not even the strongest ship in the Alliance and/or Citadel races had a weapon even close to the Reapers cannon, so basically it's a bunch of small kiloton shots hitting it. For some reason in the future they were never able to make nuke cannons I guess :P
@Jinbeifan1: Turns out that it took a brain-dead Sovereign and a direct attack on Sovereign with it's shields down with the Normandy to actually blow him up.
Still, we recognize it took several minutes of bombardment, then a brain-dead status for Sovereign for a fleet of ships which could certainly bust a mountain collectively. We can probably assume that the fleet would have lost if Shepard hadn't made Sovereign brain-dead, as the shields would have held.
@CerusSerenade: Sure, I guess collectively they could make up to 1 megaton collectively after time, but a single bijuu bomb has a power around 100 megatons, and charged up all together they can reach the high hundreds of megaton, nearly reaching a gigaton