Legendary Mexican professional wrestler and trainer Rey Misterio Sr., who is WWE Hall of Famer Rey Mysterio’s uncle and WWE Superstar Dominik Mysterio’s great uncle, has died at the age of 66.

Misterio’s son, Miguel Aarón López Hernández, shared the news on Facebook.

Per Sam Palmer of Wrestling Inc., Misterio turned professional in 1976 and remained active until 2009. He did come back a few times for matches, however, with his last one occurring in 2023.

Misterio starred in multiple Mexican promotions, including World Wrestling Association. He won the WWA World Junior Light Heavyweight Championship once and also earned the WWA Tag Team Championship with Rey Mysterio Jr. as well.

Misterio also appeared in WCW Starrcade in 1990, taking part in a tournament. He and Konnan defeated Norman Smiley and Chris Adams in the quarterfinals before losing to Scott and Rick Steiner in the semifinals.

Per Thomas Lawson of SE Scoops, Misterio started a gym in 1987 alongside professional wrestlers Negro Casas and Super Astro. He trained the likes of talents like Konnan, Psicosis and Mysterio as well.

Per Ben Flanagan of al.com, Misterio was inducted into the Tijuana Sports Hall of Fame in 2006.

Dominik Mysterio and his sister, Aalyah Mysterio, shared their reactions upon news of the tragic passing.

Many on social media also expressed their condolences and fond remembrances.

Condolences, thoughts and prayers go out to the family during this difficult time. The Mysterios are also still grieving the loss of Roberto Gutierrez, Rey Mysterio Jr.’s father and Dominik’s grandfather, who passed away on Nov. 17 at the age of 76.