The Emperor's special reserve guard functioned as a starfighter squadron providing a reserve defense force for Emperor Palpatine.
Following the attack on Palpatine's C-3 passenger liner Excalibur—an assault suppressed by Maarek Stele—Imperial Intelligence uncovered that two pilots from Mu Squadron (Z-Mu Squadron), part of the fleet belonging to the treacherous Grand Admiral Demetrius Zaarin, were also part of the Emperor's special reserve guard. This finding revealed the presence of Zaarin's spies deeply embedded within the Imperial Military structure.