The Fifth Battle Cruiser Division is a unit within the Lost Fleet. At the time of the flight from the Syndic home system, the Fifth Battle Cruiser Division consisted of the battle cruisers Invincible, Repulse, Furious, and Implacable, commanded by Commander Jaylen Cresida of the Furious
The Repulse was lost during the retreat to the jump point in the Syndic home system, and the Invincible was lost in the Ilion System. The Fifth Division's remaining two battle cruisers both made it back to Alliance space, but the Furious was lost with all hands during the defence of Varandal.
When the Fleet was reorganized post-Varandal, the Implacable was transferred to the First Division, and the five Adriot-class battle cruisers newly assigned to Admiral Geary's First Fleet -- Adroit, Auspice, Assert, Agile and Ascendant -- were added to the reconstituted Fifth Division.