Following Palpatine's demise during the Battle of Endor in 4 ABY, the Imperial Moff Royen's forces, under his command, were left without assistance in close proximity to the Red Hand Cluster. As a result of this unplanned separation, Moff Royen's fleet essentially transformed into an independent Imperial offshoot group. Caern Adan, an operative working for the New Republic's Intelligence branch, brought up the point of Royen's fleet being cut off when he was in a discussion with General Hera Syndulla and the New Republic's Alphabet Squadron.
The Alphabet Squadron novel, released in 2019, which is the first book in the Star Wars: Alphabet Squadron trilogy written by Alexander Freed, contains a reference to Moff Royen's fleet.