LAS VEGAS -- It was only Tuesday of UFC’s International Fight Week, which means the Mandalay Bay Events Center was relatively deserted.

The venue will host not one but two live UFC cards this weekend, but there’s little reason to be here until then. Nevertheless, a group of approximately 35 to 50 serious fight fans accumulated near one entrance, seeking autographs.

One of the men they had hoped to meet was actually inside the arena, but they were unlikely to catch him.

BJ Penn cherishes his fans, but he couldn't afford distractions this week. He avoided the casino floors and even spent his nights away from the Las Vegas strip.

Inside the press area of the arena, Penn, 35, unpacked a small meal that consisted of basically raw greens. He was upbeat, as he weighed in at 148 pounds on the UFC’s official scale -- a weight he says he hasn’t been at since age 19.

Penn, who fights Frankie Edgar for the third time at "The Ultimate Fighter" finale on Sunday, is a fascinating interview -- mostly because his career has been incredibly unique. At one point in our conversation, he stated the obvious.

“Fighting, to me, has always been something different than what everybody’s else opinion is,” Penn said. “I’ve never believed what everybody else has.”

A lot of mixed martial artists are popular. Few are outright loved the way Penn is. There are several reasons for it, but if you had to pinpoint one, it’s probably that he embodies the attitude fans like to think a fighter should have.

Penn has gone out of his way to find the most impossible challenge throughout his career. He will always pick a fight with the most intimidating figure in the room.

BJ Penn, left, has never been one to turn down a tough assignment throughout his long and distinguished career. Ed Mulholland for ESPN

There are countless examples of this. An obvious one is when Penn fought Lyoto Machida. There comes a time in every new MMA fan’s life when, while researching old fights, they sit back and say, "Wait -- timeout. BJ Penn fought Lyoto Machida?"

Fourteen months after Penn won the UFC welterweight title against Matt Hughes in January 2004, he appeared as a self-described “fat 185 pounds” in a fight against future UFC light heavyweight champion Machida in Japan. He lost via decision.

One largely unknown fact about the fight is that Penn actually wanted to fight Japanese heavyweight Kazuyuki Fujita. He eventually settled on Machida.

“In reality, BJ wanted to fight Fujita,” Machida recalled. “Fujita and I had the same management back then. He didn’t want the fight and said, ‘Lyoto, you go.’ That’s how BJ ended up fighting me.”

When reminded of this, Penn shrugs as if a severely bloated lightweight wanting to take on a full-size 240-pound heavyweight is a perfectly normal thing.

“We were thinking we would be faster, right?” Penn said. “That was the thought.”

That kind of approach has defined Penn’s career -- and possibly shortened it. Since losing the UFC lightweight title to Edgar in 2010, Penn has competed exclusively at welterweight. In his last two fights, he’s been badly beaten up.

His longtime coach and friend Jason Parillo, who once threw in the towel for Penn when he fought welterweight Georges St-Pierre in 2009, has spent a career trying to persuade Penn to fight entirely at 155 pounds.

Parillo was noticeably absent from Penn’s corner when he fought Rory MacDonald in December 2012. Parillo believes it’s because Penn knew he despised the fight.

“He knew I didn’t agree with him going to fight Rory MacDonald,” Parillo said. “I just didn’t know where the fight was going to put him. He probably thought, ‘Jason doesn’t agree with this, so I’m going to do it how I’m going to do it.’

“I believe he is more talented than these guys at welterweight; but when the talent is close, the size comes into play. We end up in the hospital when we lose at 170.”

At a UFC 175 prefight news conference in May, a reporter read back to Penn a statement he had once made in a previous interview.

The quote read: "There’s just something about BJ Penn that gets people amped up. You don’t know what’s going to happen but something is going to happen. He might disappoint you, make you happy, make you cry or make you jump out of your chair, but he’ll do something to you."

The reporter then asked: Is that BJ Penn still here?

Those close to BJ Penn, right, weren't convinced a fight against Rory MacDonald made total sense. Rod Mar for ESPN

In reality, that Penn never left. That description is BJ Penn for better or for worse. His potential has always been intoxicating to watch -- regardless of whether he was realizing it or wasting it.

The better question might be: How much of Penn’s potential remains and how much of it has been chipped off while fighting men 20 pounds larger than him?

For Penn, the present isn’t reliant upon the past as much as people make it out to be.

“There is some kind of fascination with who I used to be and who I am now,” Penn said. “People are always trying to look at it. I don’t know if it’s a curse or a blessing.

“When the whole fighting thing started, I never knew at the end it was going to be all about your record. I never had that mentality. I wanted to fight everybody.”

In the last two-and-a-half years, Penn (16-9-2) has nearly retired twice. Last year, he underwent corrective surgery on his left eye to repair cataracts that were affecting his vision.

The former two-division UFC champion doesn’t know whether Sunday will mark the end of his fighting career. When talking about it, he sounds like he knows retirement might be the best, safest choice.

But in Penn’s case, that has always been the hardest path to take.

“The plan is to go in on Sunday, take Frankie out and then sit down and figure out what’s the smartest thing to do,” Penn said. “You know once I win, it will be, ‘I want to fight this guy, this guy and this guy!’

“Of course I can’t retire on a win -- but then, I can’t retire on a loss either.”