In the Star Trek fictional universe, the Klingon Empire is a major interstellar power, with the seat of power located on Qo'nos. Their ships are basic, yet well-equipped for combat. Their military is known as the Klingon Defense Force, abbreviated KDF, and the advantages of their ships lie in numbers, and the use of cloaking devices for hit-and-run attacks. The Klingon Empire has been featured in many Star Trek video games, almost always as an antagonist within the story.
In Star Trek Online, the Klingon Empire is at war with the United Federation of Planets, and had conquered both the Gorn and the Nausicaans by the year 2409.