It's the Old Guard vs. The New at UFC 212 on Saturday in Rio de Janeiro, as Jose Aldo attempts to chase off a confident interim titleholder in Max Holloway.

For years, Aldo was the King of the 145-pound division, until a 13-second knockout loss to Conor McGregor in late 2015 shattered his invincibility.

Since then, it's been strange times for Aldo. He reclaimed an interim featherweight title by defeating Frankie Edgar last July, but then threatened to retire later that year after the UFC failed to produce a rematch with McGregor.

On the surface, UFC 212 looks like business is back to usual. Aldo defending the title, at home, in front of what should be a raucous Brazilian fan base. We'll see if it produces a familiar result.

Here's everything you need to know about the UFC 212 main event, in ESPN.com's latest version of the Cheat Sheet.

Max Holloway and Jose Aldo square off Saturday at UFC 218 in a rematch from their July bout. ESPN.com Illustration

Jose Aldo (26-2) vs. Max Holloway (17-3)

Unified featherweight championship

Odds: Aldo -145; Holloway +125

Aldo says he's moved past McGregor loss, but world hasn't

One of the most buzzworthy quotes of the buildup to UFC 212 came from commentator Joe Rogan, who plainly stated on his podcast that Aldo's legacy has been forever changed by that loss to McGregor.

"Aldo's legacy and reign is always gonna be tarnished by that 13 seconds against McGregor," Rogan said.

If that is reality, it is an unfortunate one (which Rogan goes on to note). Aldo is unquestionably the most decorated 145-pound fighter in the sport's history, with just one loss in the past 11 years. There would be something tragic about his entire career coming down to a 13-second encounter with McGregor.

Aldo, 30, told reporters on a recent conference call that he was sick of discussing McGregor -- understandable, considering he faces a tough challenge in Holloway this weekend. The Brazilian champion was also extremely frustrated late last year, when McGregor opted to move to lightweight and fight Eddie Alvarez in November instead of granting him a rematch.

This week, however, he has spoke publicly about future fights at 155 pounds -- something fans have waited for him to do for years -- and his coach, Andre Pederneiras told ESPN.com that a McGregor rematch remains the goal.

"He just wants to fight Conor and that's it," Pederneiras said.

That actually supports Rogan's stance on Aldo's legacy though, which is sad but not untrue. Aldo faces a legitimate, hungry challenger in Holloway this weekend, but even a win in this spot wouldn't erase the McGregor loss.

The only thing that would is probably a second fight against him. Whether or not Aldo will ever learn how to combine his in-cage performances with a strong enough media presence to get the Irish star's attention again, we'll see.

Max Holloway has won 10 consecutive fights heading into his UFC 212 matchup with Jose Aldo. Rod Mar for ESPN

"I want to be the best guy ever to do this"

If Aldo is, in some ways, trying to salvage a legacy -- Holloway is just getting started on one.

Holloway is 25 years old and in a pretty similar situation to where Aldo was five years ago at the same age. He has a UFC belt around his waist (albeit, interim) and is riding a 10-fight win streak. At this same point in his life, Aldo was the undisputed UFC champion, coming of his second defense.

If there is something to be concerned over regarding Aldo's mindset, less than 12 months removed from stating he wished to retire, Holloway seems likely to expose it.

Whereas Holloway, of Waianae, Hawaii, was not Aldo's first choice in opponent, Aldo has been Holloway's target since he signed with the UFC.

"Look, he's one of the greatest to do it," Holloway said. "Like I said before, since I was 17, I watched this guy. He stayed on top of the division. Now it's time for a new era. Right now, we've got business to take care of. I can't wait to fight this guy.

"Everybody can get a belt. I don't care. I want an undisputed career. I want the best damn career. I want to be the best guy ever to do this. When I'm done, a long time from now, people will still be talking about my name as being the undisputed best fighter of the world, not only of the featherweights."

ESPN

Key Stats

Aldo: 26-2 (8-1 UFC); making first defense of UFC featherweight title (second reign as champion)

Aldo: 7-0 in UFC fights that went into Rounds 4 and 5

Aldo: 69.7 percent significant strike defense, according to FightMetric (second highest in UFC featherweight history)

Aldo: 3-0 in UFC fights in Brazil (2-0 at Jeunesse Arena)

Holloway: 17-3 (13-3 UFC); won UFC interim featherweight title at UFC 206 in December

Holloway: 10-fight win streak (1 of 6 fighters in UFC history with win streak of 10 wins or more)

Holloway: 67.3 percent significant strike defense, according to FightMetric (fifth highest in UFC featherweight history)

Holloway: 12 wins in UFC featherweight division (most all time)

Jose Aldo is coming off a unanimous decision win against Frankie Edgar at UFC 200. Buda Mendes/Getty Images

Fight breakdown: What to make of Aldo now?

For years, he was considered one of the best pound-for-pound fighters in the world. One fight doesn't change that -- but it is something to consider when breaking down this fight.

Let's just assume Aldo is in great spirits. He's motivated and doesn't feel any additional pressure to chase down McGregor. It's back to business as usual. It's still, stylistically, a challenging fight.

The easiest explanation for this is that Aldo is facing an opponent who, at least we don't think, needs to take him to the ground to win. Holloway's bandwagon has hit max capacity in recent years because of his ability to be flashy and fun, but also the maturity that is required to win 10 consecutive fights in the UFC. He's always been a violent Hawaiian, but it's been in recent performances that he's shown the intelligence and temperament of a champion.

Holloway's game plan is where this matchup becomes most interesting. As much as we may speculate on how motivated or happy Aldo is to be here, we can be relatively confident about his strategy. He's a patient striker, which in some ways is why he has never fully been embraced by action-obsessed fight fans.

In the McGregor fight, Aldo looked a bit stressed and he opened up with a wide left hook very early in the fight. When he came back to the cage seven months later against Edgar, it was the old Aldo -- maintaining that good amount of space between he and his opponent, counterstriking, landing the jab and leg kicks. Winning rounds. It's hard to take a round against Aldo, let alone three in a five-round fight.

Holloway is beaming confidence going in, but this is a stage and opportunity he's never quite had. Setting a high pace against a champion who has had some cardio questions is a good idea, as long as it's done under control and it's set up well. Holloway has more versatility on the feet and he's unpredictable, but even at five years older, Aldo will likely have that speed and power advantage he's carried throughout his entire career.

There's an onus on Holloway to get going early, which will be interesting to watch unfold. You can't afford to dig a hole on the scorecards against Aldo. We know how that story ends all too well.

Prediction: Aldo by decision, 48-47.