In Stephen King's Revival, the preacher who performs faith healings is Charles Jacobs.
Jacobs begins the novel as a Methodist minister who arrives in Harlow, Maine, and becomes acquainted with young Jamie Morton. His early reputation for healing is linked to electricity: he uses an electrical device to restore the voice of Jamie's brother after a skiing accident. The event appears miraculous, although Jacobs later suggests it may have been a placebo effect.
After the deaths of his wife and child, Jacobs rejects religion and leaves the ministry. Years later, he travels with revival shows, presenting himself as a faith healer. His treatments do produce dramatic results, but they also cause disturbing visions and destructive psychological effects in some patients.
Jacobs is not Randall Flagg, Kurt Barlow or Leland Gaunt. Those are separate supernatural figures from King's wider fiction. Charles Jacobs is specifically the conflicted minister and electrical experimenter at the center of Revival, published in 2014.