The MMA community is mourning the heartbreaking, sudden passing of flyweight contender Allan Nascimento. UFC announced the news on Monday.

“This morning, Monday, August 3rd, our beloved flyweight fighter, Allan Nascimento, was found unresponsive after suffering an apparent heart attack in his sleep,” the promotion wrote on X. “Despite the efforts of the responding medical team, he was pronounced deceased at the scene. Our thoughts and deepest condolences are with Allan’s family, friends, teammates, and loved ones during this incredibly difficult time.”

Nascimento’s untimely passing sent shockwaves through the sport, but perhaps no one felt it more deeply than lightweight legend and BMF champion Charles Oliveira. Sharing a photo of the two embracing in his Instagram story, ‘Do Bronx’ posted an emotional tribute to his longtime Chute boxing teammate and close friend.

“Today I lost a brother,” he wrote in his native Portuguese. “Thank you for always being there, for sharing the mat, the track, for the words.

“I only have gratitude for having you by my side, brother, in training, in battles, and in our conversations. I love you, kid; you were awesome.”

For Oliveira, ‘Purro Osso’ was more than just another teammate. He trained with Charles Oliveira, Elves Brener, and numerous other UFC fighters regularly at Diego Lima’s Chute Boxe Academy in São Paulo, Brazil. He also served as their trusted cornerman in many of their biggest fights.

Nascimento was one of the gym’s longest-tenured athletes, having been with Lima for over 16 years, joining the team at its inception. This is why the BMF champion was devastated by his tragic death.

Allan Nascimento, born in São Paulo, Brazil, on September 11, 1991, got the nickname ‘Puro Osso’ (“All Bones”) as a skinny 15-year-old when he first walked into a Muay Thai gym. Although his parents were initially opposed to him pursuing a fighting career, they soon became some of his strongest supporters after seeing his dedication to the fight game.

The 34-year-old had amassed a professional record of 22-7 in nearly 15 years of being a pro MMA fighter. After establishing himself as one of Brazil’s top flyweight prospects during the country’s MMA boom heralded by Anderson Silva, he competed on Dana White’s Contender Series in 2018, suffering a loss, before entering the UFC three years later.

However, just weeks before his UFC debut, his father passed away. ‘Purro Osso’ had described it as “the hardest moment of my life,” and since then, he had carried a picture of his father with him every time he walked out for a fight.

Despite losing his promotional debut to Tagir Ulanbekov in 2021, Allan Nascimento bounced back well, defeating Jake Hadley, Carlos Hernandez, Jafel Filho, and Cody Durden, compiling a UFC record of 4-2. His last bout against Mitch Raposo came on June 20 at the Meta Apex, barely a month and a half ago. Though he fought on for the entire three rounds, he lost a very narrow decision.

One of his most notable victories came against Hernandez at UFC Fight Night 217 in January 2023, when he executed a standing rear-naked choke while Charles Oliveira watched proudly from his corner.

“How could I not get the submission with this man in my corner?” Nascimento said in the post-fight interview about Oliveira.

Outside the cage, the BJJ specialist had often spoken about how his time as a cornerman, especially for Oliveira, helped him become a stronger fighter, believing that the experience taught him to believe his own coaches’ advice when it came time for him to fight.

So, it’s no surprise that the fighter with this level of dedication managed to touch several lives, and his passing has left the fight world in mourning.

Following the UFC’s announcement, fighters from across the sport flooded social media with tributes.

Amanda Lemos simply wrote, “RIP 🙏.”

Uploading a video of her with Allan Nascimento on her Instagram, Norma Dumont wrote, “We will always remember him this way: Smiling, cheerful, and caring towards everyone and everything around him. It was an honour to share the mat with you. Rest in peace.”

Former UFC title challenger Demian Maia wrote: “My God… I can’t believe it. My deepest condolences to the whole family. 💔💔💔”

Former flyweight champion Brandon Moreno also commented, “My heart goes out to Alan’s family and all the team. 🙏”

Henry Cejudo reacted with, “❤️❤️❤️🙏.” He was joined by Gilbert Burns, who first responded with a series of heartbroken emojis: “🥺🥺🥺🥺🥺🥺🥺🥺🥺🥺🥺🥺🥺.” Burns later added another message in Portuguese: “Que tristeza.” (English: “How sad.”)

Former UFC bantamweight champion Merab Dvalishvili also shared his condolences, posting: “💔.”

More names chimed in, such as UFC Women’s Strawweight Champion Mackenzie Dern, who commented: “🥺🥺🙏🙏.”

Former UFC light heavyweight champion Maurício “Shogun” Rua also shared his condolences: “May God comfort the family’s heart 🙏🙏.”

Luana Santos has been left truly heartbroken, as he wrote in Portuguese,

“Meu Deus 😢” (English: “My God”). Jhenny Andrade commented, “😭 RIP,” while Song Yadong also paid tribute with “🙏🙏🙏”.

Allan Nascimento leaves a legacy that extends far beyond his six UFC bouts. Whether as a competitor, cornerman, or training partner, he won the respect of teammates and opponents, making Monday’s heartbreaking news one of the sport’s most painful losses in recent memory.