Pac, whose real name was Benjamin Satterley, has died, All Elite Wrestling confirmed Sunday.
AEW were "saddened" to announce the death of the wrestler, who was 40 years old, and sent condolences to his family and friends. He had competed Saturday in Chicago at AEW's "All Out" event, but his passing was confirmed on Sunday.
No cause of death was announced.
Satterley was from Newcastle, England, and began his wrestling career in 2004. He captivated fans "with innovative high-flying moves and incredible in-ring ability," AEW said.
He held championships in the AEW promotion and "competed in some of the most memorable matches in AEW history."
Satterley competed for World Wrestling Entertainment before joining AEW, where he was known as Neville inside the ring.
AEW president Tony Khan paid tribute: "Benjamin Satterley defined excellence, as a beloved husband and friend to his many loved ones, and in his wrestling knowledge, skill, unprecedented athleticism, professionalism, consistency and dedication to the sport that he loved and traveled the world to pursue. May Ben rest in peace."
Will Ospreay, a fellow Brit, said: "The greatest export from our country. Also the greatest human being. Honoured to have shared the ring with you so many times. You truly are such a hero to myself and many others."
AEW's Kyle Fletcher said: "Pac is one of my favorite wrestlers of all time. I was lucky enough to meet my hero, work with my hero, but even more lucky to get to know him. He was a better man than I ever could have hoped for. I am heartbroken. I love you, Ben. Rest easy mate."
Wrestling legend Paul Heyman added: "What a tremendous talent and even finer human being. My most profound condolences to all who knew him. A truly terrible loss!"
Stephen Farrelly, best known for his WWE stint where he known as Sheamus, said: "I can't believe it. Ben was an incredible performer and an even better fella. Salt of the earth, humble, a pleasure to be around and loved by everyone in the locker room. I first saw him wrestle in 2005 and couldn't believe what I was watching. I'd never seen anything like him. He truly defied gravity. Rest in peace, Ben. There won't be another like you."
WWE's Natalya added: "I am so sad to hear this news. Pac was always so respectful and kind to me, especially during his time at NXT when he and TJ [Tyson Kidd] were working a lot together. I'll always remember how passionate Pac was about wrestling, but equally, how much respect he showed everyone around him.
"Every time TJ was in the ring with him, he wanted to make Ben proud and be his absolute best. That always stayed with me and said so much about the kind of person he was.
"My heart goes out to Pac's family, his friends and everyone who loved him. This is an immeasurable loss. I'm so grateful I had the chance to know him."
Danhausen called him "one of the kindest, most welcoming people in a locker room" while Becky Lynch said he was "one of the best in every way possible."