It's interesting to consider that Daniel Cormier's pursuit of becoming just the fifth two-division champion in UFC history and the second to do so simultaneously never would've happened had it not been for an unbreakable bond that continues to this day. 

Cormier (20-1, 1 NC), the UFC's light heavyweight champion, will challenge heavyweight titleholder Stipe Miocic in the main event of Saturday's UFC 226 card from T-Mobile Arena in Las Vegas in a move that only came to be thanks to the chronic injuries that have sidelined Cain Velasquez, Cormier's friend and training partner.

The 35-year-old Velasquez, a two-time UFC heavyweight champion, is whom Cormier has long credited with helping him evolve so quickly from an amateur wrestler to a mixed martial artist and Strikeforce World Grand Prix heavyweight winner while working together at American Kickboxing Academy in San Jose. It's also because of that mutual respect that Cormier decided to move down to 205 pounds in 2013 while Velasquez was UFC heavyweight champion in order to avoid them ever having to fight -- a move that began the defining chapter of Cormier's career. 

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"It wasn't that difficult [of a decision] because I knew that my dream was to become the champ and I, at that time, thought there was no way that Cain would ever lose," Cormier told CBS Sports. "I was like, 'Man, as long as he is champion, I'm not going to get a chance to fight for the belt or become a UFC champion.'"

Unfortunately for Velasquez (14-2), following a 20-month stretch of inactivity due to injury, he did eventually lose the title for the second time when he was submitted by Fabricio Werdum in June 2015 at UFC 188. He has fought just once more in the three years since that date and has lived in an alternating flux of imminent return and heartbreaking delay due to various injuries and medical issues.

Yet Cormier still looks back on his decision to give up an unbeaten start to his heavyweight career and make such a difficult weight cut without any regrets or difficulty.

"I needed to do this to accomplish my ultimate goal of why I got into the sport," Cormier said. "I told Cain and he said, 'Can you make the weight?' I said yes and he said, 'Then I will do anything I can to help you become a champion.' That is how it has been since Day 1 and now that I am going back up to heavyweight, no ill feelings towards Cain. He has been in there day in and day out trying to help me accomplish that goal because that's what we do for each other, we try to help each other become the best."

While Cormier will likely be forever defined by his tumultuous light heavyweight rivalry with Jon Jones and a 205-pound reign which included memorable victories over Anthony Johnson (twice) and Alexander Gustafsson, the case could be made that DC was an even more dominant force during his previous incarnation as a heavyweight. 

One-sided victories over the likes of Antonio "Bigfoot" Silva, Josh Barnett, Frank Mir and Roy Nelson certainly back up that statement as Cormier said he relied on his advantages of speed and cardio in those days to outwork larger opponents. 

"Those guys hit hard and are strong but because they hit so hard, they tend to throw everything hard and they get tired faster," Cormier said. "I have fought some guys with fantastic cardio at 205. Alexander Gustafsson and Jon Jones have phenomenal cardio. The vast majority of the time, the pressure and pace that I fight at will make guys wilt. At 205, it takes a little bit longer for them to wilt and at heavyweight they get tired a lot faster and I can sense it in the fight."

Velasquez and Cormier remain close friends and training partners. Getty Images

But Cormier, who claims the major difference between him as a heavyweight is not having to stress about losing a set amount of weight during each training session, would prefer to squash any idea that he will end up facing Velasquez one day now that they are in the same division. 

"I truly do believe [Velasquez] is the greatest heavyweight of all-time and when he's healthy again, he will become the champion again," Cormier said. "That's not like one of those deals from five years ago where, 'What do you do DC?' No, if I'm the champion of both weight classes and he's healthy, by the time he wins once and earns that title shot I will probably be retired. And, if not, I would go back to 205 anyways. That's the weight I really do enjoy fighting at."

Cormier has listed March 20, 2019, the date of his 40th birthday, as the day he will call an end to his MMA career and has a dream, two-fight exit plan of a trilogy fight against Jones and a showdown with former heavyweight champion and current WWE superstar Brock Lesnar, provided both finish USADA suspensions for doping in time. 

There has to be a competitor deep inside of Cormier who wonders how he might fare against Velasquez after so many years of intense sparring, right? And there has to be part of him who knows, if a fight needed to happen, that he would find a way to be victorious, correct? 

"No. It would be a nightmare to fight Cain Velasquez in a fight," Cormier said. "It would be crazy. It honestly feels impossible to fight Cain Velasquez in a fight. So when I watch him lose to Werdum and I watch him lose to Junior dos Santos, I'm still amazed that it actually happened because he's that good."

In January, shortly after the announcement of the Miocic-Cormier, Velasquez sent out a cryptic tweet teasing that a meeting between the two of them could be in order if Cormier wins and Velasquez gets healthy. 

Asked to explain himself days later during an interview on The MMA Hour, Velasquez seemed to initially feed the speculation before clearing things up. 

"What did I mean by that?" Velasquez said. "Things could get interesting, man. He's at heavyweight, I'm at heavyweight. What am I gonna drop down? I don't know. Things could get interesting, yes. We don't know how things are going to play out. I think it's cool what he's doing, he's going up in weight, but s--- he's fought there before at heavyweight so he's gonna do it again.

"Would I ever fight him? No, I wouldn't. I wouldn't fight him. I think he feels the same way. We're teammates, we're friends, we've done a lot with each other. I think it would be easy, me and him, just because we spar so much. S---, it would just be another day at the office."

As usual, Velasquez has played a central role in helping Cormier prepare at AKA for Saturday's fight. From Cormier's perspective, the chance to enhance and elevate his legacy outweighed both the danger of facing a puncher like Miocic so late in his career and whatever juggling needs to be done so he and Velasquez can thrive without facing one another. 

"I like to chase dreams," Cormier said. "I've always said that I want to do something that when I'm gone and done with this sport, everybody talks about it still. Becoming a two-division champion does that. Your dream of becoming a champ, once realized, you have to start striving and shooting for bigger things and this seems like the biggest thing that I could've accomplished.

"Yes, I am rightfully the underdog. He's the heavyweight champion so yes, I'm the underdog and I deserve to be. But that doesn't determine how I approach the fight and it does not determine how I intend to win the fight."