WWE Hall of Famer Paul Orndorff, who was known as "Mr. Wonderful," has died at the age of 71, his son announced on Instagram Monday.

Orndorff was suffering from dementia prior to his death, which Travis Orndorff said was caused by chronic traumatic encephalopathy (CTE), a brain condition caused by repeated blows to the head.

"Many will remember his intensity. But if I could only get you to understand and see his heart. He will always be Pop, Paw Paw, and Daddy at home," Travis Orndorff wrote. "And as much as many of you hated him as a wrestler, he absolutely loved you for it. He was an amazing father that showed me more love than I ever deserved. I love you Daddy."

Paul Orndorff joined a class action lawsuit against the WWE in 2016 that said wrestlers suffered "long term neurological injuries" and the WWE "fraudulently misrepresented and concealed" the injuries, but the lawsuit was dismissed in 2018.

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Born in Brandon, Fla., Orndorff played running back at the University of Tampa and was drafted by the Saints in the 12th round of the 1973 NFL Draft. He never played in the NFL.

Orndorff started his wrestling career in 1976 with Mid-Southern Wrestling and joined WWE — known then the WWF — in 1983. He wrestled for WWF until 1988 when he was forced to retire due to injury, but he later returned to the ring, beginning with WCW in 1990.

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Known for his strong frame, Orndorff was one of of Hulk Hogan’s biggest foes in the 1980s. He was in main event of the first WrestleMania in 1985 at Madison Square Garden, teaming with Roddy Piper in a losing effort against Hogan and Mr. T. Orndorff inducted into the WWE Hall of Fame in 2005.

The wrestling world was devastated by the loss.

Paul ‘Mr. Wonderful’ Orndorff has died at the age of 71. (Photo by Chris Farina/Corbis via Getty Images)

"Just got slammed with the Paul Orndorff news," Hogan wrote on Twitter. "RIP, my brother. Love you and thank you for always making me fight for everything in our matches. Heaven just got even more Wonderful."

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"So Sorry To Hear Of The Passing Of Paul Orndorff aka Mr. Wonderful aka The Brandon Bull," Ric Flair tweeted out. "Great Guy, Legit Tough! He Was Another Amazing Athlete That I Had The Pleasure Of Wrestling An Hour For The NWA Championship On Many Occasions! Rest In Peace!"

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Added former WCW executive Eric Bischoff: "So sorry to hear this news. I always enjoyed working with Paul. He was a good friend to my son Garett and I and we shared some memorable times away from the wrestling business. Rest easy, my friend."