An emperor is a ruler, often unilateral and dictatorial, of a body, often an empire. Bodies such as the post-supernova Romulan Star Empire, the original and resurgent Terran Empire, and during periods of the history of the Klingon Empire, among others, have featured an emperor - as a male and gender-neutral title - or empress as a ruler.
- Hoshi Sato (mirror) (r. c. 2155)
- Philippa Georgiou (mirror) (2200s-2258)
- Terran Emperor (r. c.2409-present)
- Sela (2408-2410)