UFC 137: Nick Diaz vs. GSP is the Perfect Good vs Evil Fight for the UFC

Georges St-Pierre is usually one of the most calm and kind hearted fighters in MMA. 

But when Nick Diaz challenged the welterweight champ following his UFC 137 victory over BJ Penn, St-Pierre was livid. 

Diaz told fans that he believed St-Pierre faked his leg injury that pulled him from the card and was scared to fight him. 

Next year, St-Pierre will get his chance to prove that he is not scared of Diaz, and is the better fighter. 

Although MMA doesn't put much focus on making their fighters good guys or bad guys, there is no doubt that St-Pierre will play the face while Diaz will be the heel. 

The match-up between St-Pierre and Diaz almost plays like a comic book. 

St-Pierre is always portrayed as the calm, clean cut and kind fighter who is not afraid to discuss his fears openly. 

Some may claim that St-Pierre complaining of injuries in and outside of his fights make him look like a cry baby. 

However, it also builds his hero character even higher. Despite having eyesite trouble in one fight or a pulled groin in another, St-Pierre continued to fight through and win the battle. 

Even outside of the Octagon, St-Pierre is a wet dream for the model fighter. He never gets into legal trouble, has many sponsors and endorsements, is often seen in a clean cut business suit and almost always has a smile on his face. 

Diaz is quite different. 

Diaz's persona is hardened from growing up in the rough areas of Stockton, CA. 

He rarely smiles, taunts any and every one of his opponents, has a history of smoking weed, has an attitude like he does not care about anything and often talks about not being paid enough for what he does. 

Diaz has also fought fighters outside of a sanctioned fight, including getting into a scuffle with Joe Riggs in a hospital.

While St-Pierre is the perfect fighter to market as the MMA tries to go mainstream, Diaz could scare some off because of his thug image.

Other fighters like Michael Bisping, Chael Sonnen and even Brock Lesnar could be bigger villains.

Bisping, despite being a jerk, has international appeal. Sonnen may claim he's a gangster, but everyone knows he's more respectful and less crazy than he sounds.

Lesnar, of course, is a former pro wrestler who's really a private family man. 

With Diaz there often is never a happy medium.

Much Like St-Pierre can be looked at as the UFC's perfect business product, Diaz could be seen as the company's worst nightmare.