William Jason Reso (born November 30, 1973) is a Canadian professional wrestler and actor. He is signed to All Elite Wrestling (AEW), where he performs under the ring name Christian Cage.

Reso made his debut in 1995. He wrestled in Canadian independent promotions early in his career, where he competed in singles and tag team competition with his best friend Edge. In 1998, he signed a developmental contract with the then-World Wrestling Federation (WWF, renamed to WWE in 2002) and made his debut the same year as Christian, immediately capturing his first championship in the company, the WWF Light Heavyweight Championship, in his debut match. Edge and Christian formed a tag team and gained notoriety for their participation in Tables, Ladders, and Chairs matches. They won the promotion's World Tag Team Championship on seven occasions. They are considered one of the major teams that revived tag team wrestling during the Attitude Era. The team parted ways in 2001, after which, Christian held various singles titles in WWE, including the European, Hardcore, and Intercontinental Championships.

In 2005, Reso departed WWE and signed with Total Nonstop Action Wrestling (TNA) under his Christian Cage ring name, after which, he won the NWA World Heavyweight Championship twice. He left TNA in late 2008 and re-signed with WWE in 2009, where he won the ECW Championship and the World Heavyweight Championship twice each until retiring in 2014 due to concussion issues. He was the 23rd Triple Crown Champion and 11th Grand Slam Champion in WWE history.

In March 2021, Cage made his debut for AEW, again reverting to his Christian Cage moniker, and officially resuming his in-ring wrestling career. Following this, he won the Impact World Championship on the first episode of AEW Rampage in 2021 (as AEW and Impact had a partnership at the time), and in 2023, he won his first title under the AEW banner in the AEW TNT Championship, which he has held twice. Additionally, he is a former one-time AEW World Trios Champion. In total, between WWE, AEW, and TNA, Cage has won 26 championships, including seven world championships and nine tag team titles and is regarded as one of the greatest professional wrestlers of all time. He has headlined multiple pay-per-view events between WWE, TNA and AEW, and was one of WWE's most prolific pay-per-view performers.