SEATTLE -- Could 2013 be the year of the Diaz?

If so, the two brothers will have to dispose of a pair of champions -- starting Saturday when Nate Diaz faces lightweight title-holder Benson (Smooth) Henderson in the main event of a televised UFC card at Seattle's KeyArena. Older brother Nick will likely get his chance next year against UFC welterweight champion Georges St-Pierre.

The hoodie-wearing scrappers from Stockton., Calif., are just two wins away from becoming the first family of MMA.

Inside the cage, the brothers Diaz are mean, nasty and foul-mouthed. Henderson (17-2) even instructed his sparring partners to trash-talk him during his training camp so he could get used to the verbal abuse.

Nick (27-8-1) and Nate (16-7), both black belts in Brazilian jiu-jitsu under Cesar Gracie, are slick submission artists on the ground. On their feet, they throw punches in bunches.

They have a street swagger inside and outside the cage, loyal to their friends while daring everyone else to knock the sizable chip off their shoulders.

Even their opponents are impressed.

"Nate and Nick, they're both fighters' fighters," said Henderson. "I'm a fan of Nick and Nate's. The way they bring it, they're awesome.

"If you talk to all the UFC fighters, the entire roster, and you take a poll on who their favourite fighter is, more than likely, pretty sure, you're going to get like an 80 per cent chance of Nick or Nate being mentioned."

Nick, 29, is a former Strikeforce champion who does not play well with others. UFC president Dana White yanked him from a title fight with GSP last year after he failed to turn up for news conferences with the champion in Toronto and Las Vegas.

In the cage, he is an effective striker with a cobra-like long reach. He treated former champion B.J. (The Prodigy) Penn like a punching bag in his unanimous decision win at UFC 137.

He left the UFC initially because, in the words of White, he didn't play by the rules. That included getting into a post-fight brawl in hospital with Joe (Diesel) Riggs after their UFC 57 bout in 2006.

"Nick Diaz is legitimately nuts. He's crazy," Riggs said in a 2006 interview with

Nick is a ball of contradictions. A triathlete, he is currently serving a one-year suspension for testing positive to marijuana -- not for the first time -- after his loss to Carlos (Natural Born Killer) Condit last February.

Nate, 27, is a former winner of "The Ultimate Fighter" who has fought both at lightweight and welterweight.

He is 11-5 in the UFC and has won 10 fight night bonuses, behind only Anderson Silva (12) and Joe Lauzon (11).

Both brothers walk the walk and talk the talk.

Nate famously embellished a triangle choke win over Kurt Pellegrino by flexing his muscles and showing a pair of middle fingers from his back as he applied the submission move.

Prior to his win over Donald (Cowboy) Cerrone, he inflamed matters by knocking Cerrone's cowboy hat off at the weigh-in. Nate followed it up landing a UFC-record 238 significant strikes en route to a unanimous decision.

"I think that both the Diaz brothers are completely different than everybody else sylistically," said White. "They have a style of their own that's very unique and it wins them fights."

Nate's nine wins at lightweight in the UFC are second only to the 10 recorded by Penn, Jim Miller and Melvin Guillard. His eight submission victories in the organization, tied with Kenny Florian and Frank Mir, are second only to the 11 by Royce Gracie.

The brothers were no strangers to impromptu madness in the cage at Strikeforce, where training partners Jake Shields and Gilbert Melendez both have held titles.

There was a melee with the K.J. Noons camp -- which featured Nick's famous line "Don't be scared, homie" --and a brawl in Nashville after Jason (Mayhem) Miller crashed Shields' post-fight interview after beating Dan Henderson.

"Gentlemen, we're on national television," implored announcer Gus Johnson.

Noons had called Diaz a "pot-smoking chump from Stockton." Diaz labelled Noons' father a "drunk" who should watch his son's fights from home."

For all the reasons above, the Diaz brothers draw strong reactions.

"I think they're the type of guys that land right in the middle. There's tons of people that love them and tons of people that hate them," said White. "You know how many people tell me that those guys shouldn't even be in the UFC, they represent the sport poorly and this, that and everything else. And then I get stuff from people that love them and think the Diaz brothers are the greatest things even.

"Personally I like the Diaz brothers. This is the fight business and I understand it's the martial arts and all that stuff and you're going to have guys that are martial artists and will never say a word about anybody and they'll bow and shake everybody's hands. And then you're going to have some mean nasty (fighters) like the Diaz brothers and Ronda Rousey (another training partner) that want to finish people."

There is more to the brothers than meets the eye, however.

The "UFC Primetime" series that aired in the leadup to the interim welterweight title fight between Nick and Condit showed there was more to the older Diaz than his thug-like reputation. The series showed him to be a loyal, single-minded athlete willing to dispense with the social niceties in search of excellence.

Nate, meanwhile, shows a dry sense of humour when talking to reporters.

Asked about his ever-present backpack, he said: "Ready for war, dog, I've got everything with me. Zombies coming, I'm out the backdoor with my guns and things."

A vegan who likes to eat raw as much as he can, Nate followed his brother into the gym and became a star in his own right.

Asked about his diet at Thursday's news conference, Nate replied: "There's raw food restaurants so it's not just broccoli and lettuce. It's entrees and stuff. Look it up."

Broth brothers embrace a pedal-to-the-metal approaching to fighting. They have little respect for fighters who hunt and peck for points.

"Some people are in the same category, getting paid the same amount but not even a quarter of the fighter that you are," Nate said dismissively.

In Benson Henderson, Nate will have to get past an athletic, resilient fighter who has successfully defended 28 serious submission attempts in the UFC and WEC. He also has great takedowns.

"I think it's a phenomenal fight," said Firas Zahabi, who coaches Georges St-Pierre. "It's two guys who have never been knocked out, never been submitted, have never shown any real weakness.

"I can't wait to see which one cracks first. Because those two guys, even though they've been hit hard, they've been with ground specialists, no one's come ever close to finishing them."

For the champion, a win over Nate may earn his some long-overdue respect after a pair of close wins over former champion Frankie (The Answer) Edgar.

"I don't think he has had his due yet," White said of Henderson. "He's had some tough fights, close fights where people are saying 'Oh Frankie might have won this fight.' This is the fight for him right here. Nate Diaz is mean and nasty and he finishes people by knockout, by submission.

"I think this is the fight for Ben Henderson. If Ben Henderson wins this fight decisively or if he wins a decision, he should finally start getting the respect he's due."

Nate dismissed the notion that he is getting out from his brother's shadow with this title fight.

"I'm representing for Nick too," he said. "We're the same name, same team, my brother. So I just want to do well, I don't care about a shadow or whatever. If there's a shadow to be in, it's Nick's. I think he's the best fighter in the world. I think everybody, unless they're biased, probably would realize he's the best fighter in the world. ... I'm glad to have him be my brother and my training partner."

The Diaz brothers also have their own minimalist way of talking. Sometimes you have to fill in the gaps.

Asked whether he is tired of the bad boy image, Nate replied: "Yeah, I don't really, wherever. I think it's just people try to stick it with me more than I do."

In the co-main event, former light-heavyweight champion Mauricio (Shogun) Rua (21-6) meets rising Swedish star Alexander (The Mauler) Gustafsson (14-1). White says the winner will get a crack at whoever wins the upcoming bout between champion Jon (Bones) Jones and Chael Sonnen.

"I don't think Shogun is what he was back in the day, in his highlight prime. But Shogun is Shogun, he's a legend," said the six-foot-five Gustafsson, who has a shark's tooth tattooed on his arm after every win. "I never look past anyone. I'm ready for the best Shogun."

Former lightweight and welterweight champion Penn (16-8-2) comes out of retirement to face Canadian young gun Rory (Ares) MacDonald (13-1), another Zahabi student.

The younger, bigger, more powerful MacDonald is a 3-1 favourite with some expecting him to steamroller Penn. Zahabi says Montreal-based MacDonald hits so hard in training, he has to change sparring partners every minute and a half or two minutes.

But welterweight Matt (The Immortal) Brown is not ready to count the veteran Penn out.

"I tell you this much, man. When B.J. trains hard and is in shape, we get the real B.J., I'd never bet against him. ... No matter who's he's fighting."