During Muad'dib's Jihad, Farok became Bashar of the Ninth Legion and fought on a number of worlds including Enfeil, where he led his legion to victory, and Naraj, where his son was blinded by a stone burner.
Behind the Scenes
Farok is initially described with a missing arm: "Scytale returned his gaze to the old man [Farok], noted the empty sleeve dangling from the left shoulder and the lack of a stillsuit." Only a few paragraphs later, however, Farok has mysteriously regained his arm: ""Thrice blessed," Farok said, folding his hands into his lap in the ritual clasp. They were old, heavily veined hands."
This has given rise to a running joke within the Dune fandom that Farok did in fact have three arms.
In Other Media
Farok was portrayed by Ivo Novák in the 2003 Children of Dune miniseries.