William Jason Reso is a European Canadian professional wrestler and actor. He is currently signed to All Elite Wrestling (AEW) under the ring name Christian Cage, where he is an associate of Jurassic Express. He is best known for his tenure in WWE under the ring name Christian where he performed regularly from 1998 to 2005 and again from 2009 to 2014. He also worked for Impact Wrestling, then known as Total Nonstop Action Wrestling (TNA), from 2005 to 2008 and during a brief return in 2021.

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 friend Edge. In 1998, he signed a developmental contract with WWE and made his debut the following year, 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. The team parted ways in 2001, after which, Christian held various singles titles, including the European Championship, the Hardcore Championship, and the Intercontinental Championship.

In 2005, Reso departed WWE and signed with 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 twenty-third Triple Crown Champion and eleventh Grand Slam Champion in WWE history. He also headlined multiple pay-per-view events between WWE and TNA, and was one of WWE's most prolific pay-per-view performers. After making an unofficial in-ring comeback in June 2020 and appearing in the 2021 Royal Rumble match, Reso left WWE shortly after and signed with AEW, again reverting to his Christian Cage moniker, and officially resumed his in-ring wrestling career. Following this, he won the Impact World Championship at AEW Rampage, making his return to Impact Wrestling for the first time since Slammiversary 10 in 2012.