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UFC 223 on Saturday was a special pay-per-view—and not in a good way. From fight cancellations to bus attacks, the build to card was draining.

Fans will have the chance to cleanse their palates with a pair of Fight Nights, but the next big card is a toned-down UFC 224 in Rio de Janeiro on May 12. As of this writing, the card stands as follows:

Amanda Nunes vs. Raquel Pennington

Ronaldo Souza vs. Kelvin Gastelum

Mackenzie Dern vs. Amanda Cooper

John Lineker vs. Brian Kelleher

Vitor Belfort vs. Lyoto Machida

Cezar Ferreira vs. Karl Roberson

Oleksiy Oliynyk vs. Júnior Albini

Elizeu Zaleski dos Santos vs. Sean Strickland

Warlley Alves vs. Sultan Aliev

Thales Leites vs. Jack Hermansson

Alberto Mina vs. Ramazan Emeev

Davi Ramos vs. Nick Hein

It's a much less glamorous card than Saturday's, but there is still intrigue to be found. Read on to find out about the biggest and best fights slated for UFC 224.

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The Main Event: Amanda Nunes vs. Raquel Pennington

The women's bantamweight division is in an awkward spot. Its top stars are gone, its top contenders are competing in other weight classes and the fighters who are left have no serious name value.

Champion Amanda Nunes has the unenviable task of trying to reel fans into the arena with no real bait to work with and no real nets to cast. The best option available to her? A bout in her home country against a relative no-namer, Raquel Pennington.

Despite being a low-profile opponent, Pennington's in-cage skills are legitimate. While she missed all of 2017 because an injury, The Ultimate Fighter Season 18 alumna is one of the division's most well-rounded talents, capable of delivering slobberknockers while standing and scary submissions on the ground.

On top of that, as one of the most physically powerful fighters in the division, she is one of the few capable of matching Nunes' pure physical strength.

It should be an interesting bout, but it's hard not to worry about what direction Nunes' career is going in.

Despite being incredibly talented and one of the most dominant female fighters ever seen, she just hasn't resonated with fans on any level. As the months go by and the spotlight over Nunes gets dimmer, it's hard not to chalk up the UFC's handling of her 2016 bout with Ronda Rousey as one of the promotion's all-time greatest failures.

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The Co-Main Event: Ronaldo Souza vs. Kelvin Gastelum

While there were rumors a Colby Covington vs. Rafael dos Anjos bout for the interim welterweight title would be the main or co-main event to this card, the UFC instead booked that fight for UFC 225. Sitting in second billing instead is Ronaldo "Jacare" Souza vs. Kelvin Gastelum.

Purely from a technical standpoint, this bout might just be better than Covington vs. RDA.

Jacare is entrenched as an elite middleweight. Long a submission specialist on the international circuit. The Brazilian began spreading his wings in the UFC's sister promotion, Strikeforce. There, he demonstrated impressive growth, improving his wrestling and striking with each bout and carved out a spot as a serious contender before stepping into the Octagon.

Despite owning a strong 8-2 record in the UFC, he has struggled to gain the momentum to warrant a title shot because of unfortunate injuries and ill-timed stumbles. Many feared his 2017 loss to Robert Whittaker may have killed his dreams of UFC gold, but he got back into the title hunt in January by knocking out Derek Brunson.

If he can take a win over Kelvin Gastelum at UFC 224, he might be able to force his way into a championship bout. But that's a big if.

A solid 170-pounder, Gastelum was forced to move up to 185 in 2016 after repeatedly missing weight. Though he is visibly undersized as a middleweight, his youth, quickness and striking accuracy has allowed him to hang with the division's best. A loss to Chris Weidman last year made it unclear wheter he could enjoy long-term success there, but a brutal win over former champion Michael Bisping in November put him right in the thick of contention.

With no clear contender lined up at this time, this bout is vital for both men. The winner here could be in line for a crack at the belt by year's end.

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Fight to Keep an Eye On: Mackenzie Dern vs. Amanda Cooper

Mackenzie Dern made her highly anticipated UFC debut in March, beating Ashley Yoder by split decision. Reactions to the performance were, ahem, mixed.

On the one hand, Dern's strengths were obvious. She's deceptively quick, physically strong and is possibly the best pure grappler in women's MMA.

On the other hand, those are about the only tools she has. Her striking and wrestling are both lacking, her cardio is questionable and her fight IQ was as low as one would expect of someone just 18 months into their MMA career.

Frankly, giving Dern such a quick turnaround for her sophomore UFC bout is a bad idea. Dern would likely benefit from more reps in the gym than minutes in the cage, and it's easy to wonder whether rushing her back into the Octagon might set her down the path walked by Sage Northcutt instead of the one walked by Conor McGregor.

Her UFC 224 opponent, Amanda Cooper, is likely an easier draw than Yoder was. Still, this fight has disaster written all over it.

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The Best of the Rest

Lyoto Machida vs. Vitor Belfort

Vitor Belfort is retiring. Or maybe his UFC contract is expiring. Either way, The Phenom's days as a UFC fighter are numbered, and he's likely going to be shown the door by former light heavyweight champion Lyoto Machida.

Machida is coming off a narrow, but much-needed, win over Eryk Anders in February and has the opportunity to gain some momentum by facing his fellow veteran—an opportunity he will likely make the most of.

John Lineker vs. Brian Kelleher

Brazilian UFC cards oftentimes have a few "hometown favorite squashes despicable foreigner" bouts. One of the ones slated for UFC 224 is John Lineker vs. Brian Kelleher. Lineker is a fan favorite across the globe and a staple of the bantamweight top 10 courtesy of his amazing punching power. Kelleher, well, isn't.

This is a fight tailor-made for Lineker, and it would be a bit of a shock if he doesn't win in fairly emphatic fashion.