The slave who became a soldier who became a spook who became the most important figure in the known universe.
- Conveniently an Orphan: He ended up running late to a planned family outing. By the time he got there, the place where said outing was had been launched into space, killing over a thousand people (including every other member of his family).
- Hidden Weapons: He has a knife that he made himself (which cuts through just about everything), hidden in a specially-made sheath in his arm. Yes, in his arm.
- Hurting Hero: But very stoically.
- Mighty Whitey: Invoked by the Bhor, and sarcastically deconstructed by Sten. After Sten helped the Bhor in a bad situation, they mythologized him as "the greatest fighter, lover, and drinker in Bhor history." When he learns this, he comments, "In the whole time I was there, I only got laid twice, and I lost almost every battle except the last." Not to mention that no human can keep up with Bhor alcohol intake.
- Only One Name: Officially, he's known as Sten, NI (No Initial). His first name is actually Karl, but it hardly ever comes up.
Laird Kilgour of Kilgour, called Sten's "personal thug" by the Emperor. A Scottish aristocrat who joined the Emperor's service like his brothers. Unlike his brothers, he didn't die. He also joined Mercury Corps, became a Mantis operative, and Sten's right-hand man.
- Stuff Blowing Up: He's a demolitions expert.
- The Big Guy: Holy shit is he strong. Justified, as he comes from a world with heavy gravity.
A stone-cold gorgeous female soldier with a talent for the "long-arm." Descended from the defunct warrior caste of the Jannissars, she runs away from home to become one of the few humans in the Bhor-run military. Completely and totally in love with Sten.
The leader of the Bhor, a race of Proud Warrior Race Guys
who end up on Sten's side during The Wolf Worlds
and remains a good friend of Sten's afterwards.
One of the Emperor's sidekicks and the closest thing he has to a real friend, Mahoney is the man who recruits Sten into Mantis Section. He leads the Section for the first few books, but later steps up to the plate and leads troops again.
The Eternal Emperor
The Man. The Authority. The Eternal Emperor. Since humanity first reached out to the stars, he has been the supreme ruler of the known universe. No one really knows the secret to his immortality, and after a few thousand years, people have stopped asking. Besides, he's a pretty cool dude. Things are alright under the Emperor- he's lenient, makes sure that things are run efficiently and that everything works. Not to mention, he can kick your ass in a bar fight, drink you under the table, and then fix you up with a mean Angelo Stew.
- Came Back Wrong: After being successfully assassinated by a cabal of ambitious businesspersons.
- Character Death: He's killed at the end of Revenge of the Damned and returns in The Return of the Emperor, but Sten permanently kills him in Empire's End.
- Combat Pragmatist: His preferred shipboard sidearm is a crowbar.
- Emperor Scientist: A skillful engineer.
- Everyone Calls Him Barkeep: Pseudonyms aside, he is the Emperor. That's it.
- Evil All Along: Suggested by Rykor, who notes that he was quietly killing off anyone who could be a threat to him for years, even before he died.
- The Fettered: Doesn't trust anyone with power, including himself, which is why his first incarnation arranged things so that none of his subsequent clones would be able to deviate from a moral standard enforced by the computer governing his resurrection facility.
- God Emperor: His immortality has lead some groups, such as the Cult of the Emperor, to worship him as a god.
- No Party Like a Donner Party: As a young man, he ended up on a ship that, on the way back, ran out of food. By the end of the trip, he was the only person left alive. Which meant that he was the only person who knew where to get AM2, which effectively gave him the keys to starting the Empire.
- Reality Ensues: The Emperor is the only person who knows where and how to get AM2. AM2 is used for everything from starship fuel to ammunition. So after he dies at the end of Revenge of the Damned, the Privy Council drives itself crazy trying to find where and how to get more, because they're rapidly running out of time until they run out- and then they're well and truly fucked.
- Reasonable Authority Figure: At first. After he dies and comes back, everything starts going to hell.
The first distaff half of Sten's Battle Couple
. Born on the same hell-world as Sten, Bet's parents sold her to the Vulcan corporation to pay off their debt and escape the planet. Utilizing the same ferocious intelligence that got her singled out in the first place, she escapes the lab (and the living death that faced her) and joins the Delinqs. Then one day a boy named Sten joins their group...
- The Beastmaster: By the second book, this is literally her job description; she has two trained tigers under her command.
- Disney Death: She falls down an elevator shaft to an off-screen death. This makes her return easy to retcon.
- Fate Worse Than Death: What was intended for her. The medicines given to the smart children effectively turned them into living dolls who never matured.
The Emperor's personal bodyguard is made up of Gurkha mercenaries. They are listed together here because in the series their personalities are pretty much interchangeable.
- Obfuscating Stupidity: Sten observes that the Gurkhas could be very naive, but sometimes that naivete would result in them getting exactly what they wanted.
A galaxy-renowned psychologist and preeminent criminal profiler, Rykor is frequently called upon by Mercury Corps as a consultant. She is also very good at her own kind of "wet work." Conducting interrogations and brain scans are two of her specialties.