About eight months after the Battle of Yavin, he was serving on the Outer Rim Territories, primarily as the captain of the Imperial-class Star Destroyer Reprisal, the command ship of Lord Darth Vader. In this capacity, he served a prominent role in the hunt for the Rebel Alliance fleet, and the final pacification of Jabiim.
However, Demmings was not simply a capital ship commanding officer; he held a senior rank, and he also served as liaison officer to Tiss'sharl, replacing the late Moff Giiedt. Although he could be addressed as "captain" by virtue of his direct command of Reprisal, it is possible that he was the Regional Governor of the local sector or the High Admiral of the local Sector Group, or else that he held some sort of equivalent authority as an adjutant to Vader.
- Empire 31: The Price of Power (First appearance)
- Empire 34: In the Shadows of Their Fathers, Part 5
- Empire 35: A Model Officer
- Rebellion 0: Crossroads