Upon their arrival, the Powers of Pain were faces, initially managed by Tito Santana, and feuded with WWF World Tag Team Champions Demolition (Ax and Smash), who had defeated Strike Force (Santana and Rick Martel) for the titles and then injured Martel (kayfabe). The Powers of Pain were introduced as mercenaries to help Martel and Santana gain revenge on Demolition for both the title loss and the injury to Martel. Later, they were managed by The Baron. They soon dumped the Baron and took Demolition's manager Mr. Fuji, in a double turn which made them heels and the increasingly popular Demolition faces.
After a long feud in which they failed to win the titles, the Powers of Pain were demoted to feuds with teams such as The Bushwhackers and The Rockers. In early 1990, they split up and The Barbarian went under the management of Bobby Heenan. He would have his image tweaked, changing from his Road Warrior-like mohawk and face paint to growing out his hair, dressing in fur, and wearing a helmet with reindeer-like antlers and a skull to the ring. He briefly wrestled in singles competition, defeating Tito Santana at Wrestlemania VI and facing the Big Bossman at Royal Rumble 1991, as part of the Heenan Family's feud with the "correctional officer". Shortly after, he wrestled in tag team matches—notably with fellow Family member Haku and also with Fatu of The Headshrinkers (replacing Samu)--until leaving WWF.
By mid-1994, he had returned to WWF, where he wrestled as Sione, one half of the new version of The Headshrinkers alongside original Headshrinker Fatu until leaving again in mid-1995.