Mirror Universe (Decipher)
Mirror Universe: Through a Glass Darkly is a roleplaying game supplement published by Decipher in 2005 as an eBook in Adobe Acrobat PDF format. It is the second such official supplement for the Decipher STRPG released only as an electronic document.

The book itself documents and extrapolates the evil-bent universe first encountered by James T. Kirk and crew in the  episode  and revisited several times on both  and . It chronicles the development of the Terran Empire, its rise and eventual downfall by the combined forces of the Klingon-Cardassian Alliance, and the efforts of the Terran Rebellion to wrest control back from its conquerors. It also gives gaming stats for key mirror universe personnel and technology as depicted in the various Star Trek episodes.

Book description 
From the back cover
"I had an opportunity to observe your counterparts here quite closely. They were brutal, savage, unprincipled, uncivilized, treacherous... I found them quite refreshing."
 – Spock to Kirk and McCoy, Mirror, Mirror

Through the looking glass... darkly.

Haven't you ever wanted to phaser the captain, level a helpless planet, and steal your weight in gold-pressed latinum? Now you can – on the other side of the mirror. In this setting book for the Star Trek Roleplaying Game, you can bring Federaton ideals of justice to the Mirror Universe, or revel in your own character's dark reflection. Prowl the Terran Empire with Captain Kirk of the I.S.S. Enterprise, or crush puny Human rebels with Intendant Kira of the Cardassian-Klingon Alliance. So grab your agonizer, grow a goatee, and watch your back – because in the Mirror Universe, nothing is what it seems...

Through a Glass Darkly: The Mirror Universe includes:

 Complete setting information for the Terran Empire from Star Trek and the brutal Alliance from . 
 Rules and guidelines for creating your existing character's mirror image.
 Everything you need to play a "Mirror Series," including new skills, cruel traits, and the malign Wheel of Comeuppance.
 Star Trek RPG Rules and statistics for the agonizer, the Tantalus Field, and the deadly devices of Imperial Security.
 Unsolved mysteries of the Mirror Universe to explore on your own or use in your series.

Background information 
According to this supplement, Qo'nos of the mirror universe was conquered by the Terran Empire in 2218 after a campaign beginning in the late 22nd century. The ISS Ranger warped into the Qo'nos system and demanded the surrender of the Klingons. The Klingons seized the ship and stole its technology, but they were unable to hold off the empire. Eventually Imperial Starfleet pushed its way to Qo'nos where General Order 24 was carried out, and all life on the planet was destroyed. In 2293, Qo'nos's moon, Praxis, was blown up in an act of terrorism; Klingon ships massacred the remaining Human colonists and reclaimed their homeworld.

References 
 Qo'noS

External link 
 

Role-playing games
eBooks