based on what i've learned and analyzed in Season 5 and 4 (Nothing with my opinion) I'd say it goes like this
1. Link (mostly because of the master sword)
Link is known to be able to beat ganon. Why this is high? Quite obvious if you watched season 5 but Read what I wrote for Ganondorf. Plus The Darkness and Mario stated he was the strongest of them all. However that was in the Movie, Mario and the gang have done a lot of training since then. Though it seems logical that Link is the strongest, since he is the only one who can beat...
Ganondorf here owned the Darkness, who owned (by owned I mean froze, but then again, if he wanted too, he could've killed them while they were frozen) Blaire, Decious and Bowser (Scott and Pauline aren't much xD)
3. The Darkness
As I wrote for Ganondorf, he defeated Decious, Bowser and Blaire. Blaire who managed to beat Mario (Season 4), Snake and Ken. Though Mario is probably stronger than Blaire by now due to training. If not, then wow Mario's weaker than I thought. And Wlauigi's stronger than I thought.
4. Waluigi (ish)
He DOMINATED Blaire. Who, as previously mentioned, managed to beat Snake, Ken (Season 5) and Mario (Season 4) Though beating Blaire has rendered Waluigi useless. So maybe Waluigi shouldn't be high on this list. I dunno.
While everyone got beaten by 1-2 Ninjas or one of the bosses in Episode 64, Mario easily wiped out like 4 on his lonesome. Plus he beat Decious with some effort in 61. Wow, Decious is losing his touch. Unless he succeeds in taking down the Darkness, he's really losing his reputation as a big time bad guy.
I could be wrong about some of these though. Ryu may or may not be stronger than Mario. Ryu DID train Mario and the gang in Season 4 which gave me the image that he was the strongest at the time. Though there has not been proof so, I can't make assumptions.
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