(coexisting on another dimensional plane)
This page contains information regarding Star Trek: Discovery, and thus may contain spoilers.
In the mirror universe, the Honor Guard was a cadre of Terran Empire Starfleet officers who served as bodyguards to the Emperor. They wore a variant of the Starfleet uniform with additional gold plating on the arms.
Emperor Philippa Georgiou's Honor Guard was led by Commander Joann Owosekun. In 2255, Captain Sylvia Tilly was reluctant to discuss Gabriel Lorca and Michael Burnham's treasonous plans with Georgiou in public, but Georgiou assured her that the Honor Guard could be trusted. The Honor Guard later apprehended Burnham after her assassination attempt on Georgiou failed. (DIS: "Terra Firma, Part 1")
Two years later, the Honor Guard were stationed on the ISS Charon with Georgiou when Lorca and Michael Burnham from the prime universe arrived. They were later killed by Lorca's followers during his takeover of the Charon. (DIS: "Vaulting Ambition", "What's Past Is Prologue")