Benevolent Boss: Ami is probably the first Keeper who doesn't actually consider her minions expendable. She also goes out of her way to avoid the traditional discipline techniques. This is considered a weakness by anyone familiar with Keeper tactics and Underworld customs.
Just about everyone's reaction when she defeated an Incarnation of Crowned Death by eating it.
Golem: Their creation is one of Ami's research breakthroughs. Various golems play a very important part in her plans, not the least of which is acting as her main troops, so that her living employees don't come into harm's way unnecessarily.
Heroic BSOD: At one point, Ami is forced to mind read the freshly-defeated Keeper Malleus in order to learn how to create new dungeon hearts - a piece of information critical to her further progress. At first she didn't mean to do anything but glean that info and leave him be, but as she searched his mind she couldn't ignore his other memories. Accessing them, she couldn't turn away. They were the memories of a sociopath who had been active for hundreds of years. Living through these memories was enough to give Ami a heavy PTSD. Furthermore, once she had the info she was looking for and stopped her possession of him, she promptly executed him because she couldn't allow such a monster to live. This was the first person she ever killed, so this act only added to her trauma. Following this episode, she kept having paralyzing flashbacks while awake and horrible nightmares when asleep. This state was finally ended when the Light used its power to heal her mind when she visited their temple for another purpose.
Lesser of Two Evils: How Ami is seen by some of the more level-headed followers of the Light. Notably even the Avatar, for whom Keepers are a Berserk Button advises the dwarves that Mercury is not a high-priority threat and will be more or less harmless if left alone.
Memetic Badass: In-universe example. Ami's reputation has made her this, and it's only increasing with time.
Memetic Molester: Also in-universe. Due to a series of misunderstandings, Ami is rumored to be an extreme deviant. The ultimate of these rumors is that of Ami doing something no even remotely sane person would ever try, let alone survive - raping a horned reaper. Of course, unlike just about everyone else, the dark mistresses consequently see her as a Memetic Sex Goddess instead.
One Girl Industrial Revolution: She relies on scientific knowledge from her world to solve practical problems; such as creating artificial sapphires to fund her empire or windmills to generate electricity for facilities in her dungeons. For reference, the Dungeon Keeper world considers a light bulb to be magic. This greatly aides her surprise factor, but Ami must protect the knowledge so other Keepers don't steal the ideas.
Science Hero: Has good knowledge of 20th century science and technology, as well as the mindset of an engineer.
Signature Move: She has two Senshi spells. Shabon Spray (creates a dense, cold fog in an area that Ami and her allies can see through), and Shabon Spray Freezing (launches a stream of bubbles that freeze the impact point and its near surroundings).
Training from Hell: Cathy puts her through one in order to prepare Ami for her duel with the first Horned Reaper.
Trapped in Another World: She comes to the Dungeon Keeper world's dimension from the one containing Earth, after falling into a dimensional rift caused by Jadeite during a combat between him and the Sailor Senshi.
The Medic: While he isn't the only one with healing powers, and he isn't an expert, his abilities are nothing to sneeze at. Given his lack of direct combat ability in most situations, this is his normal role on the battlefield.
And I Must Scream: Queen Beryl's final punishment for her minions' failures is Eternal Sleep, which is eternal imprisonment in a crystal that provides perfect isolation from the outside world. Meaning, the prisoner is completely immobilised and suffers from total sensory deprivation. Sooner or later everyone goes insane. While Jadeite, Mareki and Umbra were saved in time, poor Tiger unfortunately wasn't.
The Dragon: Was one of Queen Beryl's four generals, before she punished him for his failure in defeating the Sailor Senshi during the opening battle of the fanfic.
Teeth-Clenched Teamwork: Jadeite and Cathy don't get along too well, but they don't let that get in the way of what needs to be done.
Token Evil Teammate: Among Ami's closest companions. Note that by the standards of the DK world he's rather tame, as there are far worse people out there (and even among Ami's employees).
What Is This Thing You Call Love?: Dark Kingdom romance is somewhat lacking compared to Earth standards, apparently. Jadeite kind of understands this "love" thing on an intellectual level, but the only experience he has is teenage romance novels.
Marda / Amadeus, the Avatar
Berserk Button: Having her trolls comment on her attractiveness. She will give them a proper beating if she catches that kind of talk.
"MUKREZAAAAR!" the Avatar howled like a blood-thirsty animal, and then his crystal ball went black.
Amadeus was betrayed by a priest who swapped out his Mantle for a convincing fake, leading to his defeat. So whenever he sees a acolyte in a Keeper's employ, the Avatar has to restrain himself from killing the unfortunate individual on the spot.
Big Good: He was this in the first Dungeon Keeper game. He might still somewhat qualify.
Commander Contrarian: To Mercury, though subverted - Marda's questioning of Mercury's strategies actually has a very good basis. Mercury is very inexperienced compared to Marda when it comes to being in command.
Determinator: Welded a group of Trolls, a species not renowned for being particularly tough, into a disciplined force that waged a guerrilla war against a Keeper and his army of undead. She survived on a hell-hole continent with no support, waiting for the opportunity to start destroying Dungeon Hearts. All of this was to get the one object that lift the curse that Marda despises.
The Dreaded: There's probably nothing the creatures of the Underworld fear more than the Avatar.
The Juggernaut: Becomes this once he manages to regain his true form (plus his mantle, with which he broke the polymorph curse that had turned him into a troll) and the Light can aid him directly again. Goes on a slow walk towards Mercury's dungeon heart, knowing that nothing in this world and within Mercury's possession can possibly stop him. Mercury, not being from this world, manages to stop him (after throwing every spell she knew at him, to no effect) with something incredibly simple - a huge electromagnet that sticks him to the wall (due to his armor). Both he and the Light are fooled into thinking this is a very powerful spell, rather than simple physics, and thus he's forced to surrender.
Knight in Sour Armor: The utter destruction of his homeland (that he ruled over), the ensuing long struggle to survive and generally the loss of everything he cared for have heavily jaded him.
One-Man Army: Marda's trolls are extremely well trained - enough to take on vampires. Marda herself goes beyond that - she can hold her own against a horned reaper. When she turns back into her true form, which is Amadeus the Avatar (a he), he gets even more powerful. And if he also wears his mantle, he's almost invincible!
La Résistance: Leads a band of trolls that are the last living intelligent beings on the Avatar Islands, and have been fighting Zarekos' undead hordes pretty much since Mukrezar's fall (so, for about 15 years).
Brilliant but Lazy: An odd homicidal example. He's a Horned Reaper, so he's already a barely-restrained killing machine of the Dark Gods. While he was waiting for someone to reactivate the dungeon he was in, he did nothing to stay in shape. He lazed about for decades basically twiddling his thumbs. So beyond killing basic Mooks, he cannot keep up with, say, Baron Leopold in a straight bash-up.
Evil Mentor: Teaches Mercury the basics of being a Keeper. After forcing her to become one in the first place.
"Freaky Friday" Flip: Ami accidentally traded bodies with this Reaper during her first Possession attempt. She (being the Horned Reaper) went into an apoplectic rage and attempted to beat him (Ami at this point) to death. He (Ami) decided to use this as both a way to work at all hours and to punish the Reaper's disobedience. Ami temporarily stops using female pronouns to refer to himself, reasoning that being in a male body means male pronouns.
Unfortunate Implications: Being a Tentacle Monster, many think Mercury keeps him around for her own personal deviancy. While Tserk does crave physical contact, he is content to just cuddle or massage though. That doesn't stop everyone from assuming the worst and avoiding Tserk anyways, to its great frustration.invoked
And I Must Scream: A victim of Eternal Sleep (explained under Jadeite's section above). Didn't leave long-lasting consequences, thanks to her being rescued quickly enough.
Making a Splash: Mareki's special ability is being able to spew a rather impressive jet of water from her mouth. This proves to have some pretty good offensive uses.
Deadly Doctor: She's the warlock that altered Morrigan's body to that of a titanic, muscle-bound giant. Offers to similarly augment Ami's body, and is implied to know more healing/body manipulation magic than any magic user yet encountered.
Token Evil Teammate: The only one of Ami's employees that displays overtly villainous behavior; though, it is noted that when backed into a corner, she averts her eyes and admits that she had little say in the matter while working for Morrigan.
And I Must Scream: A victim of Eternal Sleep (explained under Jadeite's section above). Didn't leave long-lasting consequences, thanks to her being rescued quickly enough.
That's Gotta Hurt: Umbra has lost a limb twice so far. The good thing is that youma have excellent regenerative capabilities, and can regrow an entire limb on their own within a couple of weeks.
And I Must Scream: A victim of Eternal Sleep (explained under Jadeite's section above). Unfortunately, she wasn't released fast enough, so she went insane to the point of being almost completely catatonic. Ami was only able to cure her once she acquired the Avatar's Mantle, and in addition, Ami possessing Tiger had the unintended consequence of imprinting a good chunk of her mind unto Tiger's.
Clones Are People Too: Tiger will loudly state that she is a person in her own right, though she would argue that she isn't a clone as much as "The older and bolder sibling!"
Drunk with Power: When, after destroying the High Temple of Crowned Death, Ami passes out (mentally, as she was in the same body as Tiger, because Tiger had possessed Ami in order to save her), Tigernote who, through possessing Ami, managed to gain part of Ami's Keeper powers for the duration of the possessiondecides she's the leader now. Ami's other companions were not amused.
Green-Eyed Monster: She's envious of Ami at first, due to having her memories yet none of the connections with her friends and family (none of them even know Tiger exists, even as she knows them well).
It was clear from Mrs Mizuno's facial expression that she had trouble with the concept of suddenly having acquired a second daughter. A daughter who was older than her first, had skin covered in a strange striped pattern, and tiny horns. Finally, she let out a long sigh. "I'm glad I'm sitting down already. Well, they say that parenthood is full of unexpected surprises." She let out a short laugh. "I certainly never expected to become a mother again - with so little warning at that."
Only Known by Their Nickname: She hasn't told anyone her real name. Ami dubbed her 'Tiger' due to the black tiger-like stripes all over her body.
What Measure Is a Non-Human?: Being a Youma, this becomes a major concern with Tiger given the fact that she holds many (if not all) of Ami's memories due to losing her mind and Ami possessing her, and as a consequence she loves her mother, and still considers the rest of the Senshi her friends, much to her exasperation.
The Archmage: The Head Researcher in charge of Mercury's Warlocks.
Ax-Crazy: The first time we see him (in Nero's service), he's sitting on his throne in a room full of the bodies of Nero's spiders that he just killed. The spider carcasses were arranged by size. Oh, and the throne was made from these bodies!
Only Known by Their Nickname: At first. Ami and Jered nicknamed him Rabies, due to his physical appearance. Incidentally, this nickname is rather similar to his real name.
Psycho for Hire: After leaving Nero's service, he contacts every local Keeper to hear their offers for hiring him. He immediately joins Mercury when she tells him that his first mission would be to destroy every ghost and skeleton on the Avatar Islands - which are one of the world's three continents!
The Voiceless: Part of what makes him so much creepier and more imposing than the first reaper is the fact that he virtually never speaks, despite being intelligent enough to use magic. There is only one scene in which he speaks (three if you count saying a single word in later scenes), and it notes that his voice sounds "rusty from disuse".
Ambiguously Evil: She works for Keepers. On the other hand, she's never actually seen doing anything evil.
Girl Friday: Serves as one of Mercury's scribes and adjutants.
The Mole: Presumably. She's the only new youma named since Beryl began her plan to track Mercury. A plan that has failed to come to fruition not because Beryl failed to plant a youma on Mecury, but rather because the Light Gods aren't willing to allow the Dark Kingdom access to the Dungeon Keeper world.
Evil Genius: Don't let the fact that she lost more battles to Mercury than any other Keeper or that she ended up dying (offscreen) to Alphel fool you - Arachne is definitely competent and devious. It's just that she's facing foes who are pretty much the best of the best.
Screw This, I'm Outta Here!: When Mercury's traps and Mercury herself kill most of her attack force, Arachne decides her presence is no longer needed. Alphel did not take that well.
Villain Team-Up: With Alphel during their attack on Mercury's iceship. It didn't end well.
Voice of the Legion: Sort of. Her voice is not really a voice in the usual sense, but rather the rubbing of the chitin of thousands of insects (that make up her body) in approximation of vocal sounds. The resulting 'voice' is quite unsettling.
"It saddens me to see that standards for heroes have fallen so far," the butler agreed, hanging his head. "I will miss their proud and defiant posturing and self-righteous condemnations. But most of all, I will miss seeing their disbelieving, shocked faces when you ambush them during the pre-battle formalities, your Unexpectedness."
Ring of Power: He loves schemes that include magical rings. The Butler duly reminds him that none of said schemes that he attempted in his past life succeeded. This didn't stop him from trying again... only to succeed this time!
Smug Snake: Somewhat. As his imp Butler loves to remind him, his plans very often tended to fail or even backfire. Still, one should remember that Mukrezar is the Keeper who, with few other Keeper allies (or rather, subordinates), managed to conquer one of the world's three continents, defeating the greatest champion of the Light, his forces, and all the other Keepers active in the area. After his resurrection, Mukrezar again goes to show just why he used to be so feared.
The Starscream: To Crowned Death. He doesn't even bother to hide it particularly well. And it isn't too long before he succeeds in kicking Crowned Death to the curb.
Unknown Rival: A curious mutual case with Ami. They don't know much about each other but are pretty much moral counterparts of each other. They also have a professional appreciation for each other's cleverness.
Villain Decay: Inverted. Mukrezar is pretty much introduced as a formerly powerful Keeper, but on the other hand often unsuccessful in his schemes and not terribly competent. His performance post-resurrection, however, makes it clear that such a picture, while not entirely wrong, significantly downplays his prowess... for Mukrezar's track record since then is nothing short of spectacular. When he describes himself as the world's greatest Keeper, he's definitely not far off the mark.
Villain Protagonist: After his resurrection, Mukrezar now gets his own episode in pretty much every chapter.
A God Am I: He dominates his undead minions and insists that they worship him as a god. Which is exactly what he's trying to become.
Back from the Dead: Being a vampire, destroying his body did not mean that he was killed off for real (unlike regular Keepers), unless it was incinerated by sunlight. When Mercury did just that, he still didn't die, but was instead raised as a ghost in his temple. This was apparently a result of his research of ascent into godhood, and the properties of his temple, which is a modification of the Oracle Towers used by the heroic Shining Concord Empire.
Bad Boss: He basically treats his minions as cattle, and forces them to worship him in order to increase his powers.
Clipped Wing Angel: He might be able to dominate anyone who makes eye contact with him as a ghost, be invulnerable to normal damage, and retain his intelligence in the process. But as the Avatar notes, Zarekos can't move from the pentagram on his statue's forehead. Zarekos can't survive without the Mantle either. He also cannot have access to Keeper powers or control the ghosts and skeletons without a puppet Keeper.
Dangerously Genre Savvy: At one point, he was decisively winning the battle against Mercury. He briefly wondered whether to conserve the last of his gold (he couldn't get more, and he needed it for spellcasting, thus it was very important to him). He decided against it; he would rather continue going all-in. This is because he himself has been in the reverse position several times, and managed to snatch victory from the jaws of defeat because his enemies were winning and thus let their guard down.
Evil Genius: Zarekos is scarily competent and intelligent. He comes very close to winning the war against Mercury.
Point: the only reason Zarekos lost is because his resources were so small - had he been capable of even one more tremor spell he probably would have won.
Too Dumb to Live: Not quite. While some of his actions might qualify, Morrigan is nevertheless smart enough to manage to survive in a world of antagonistic and competitive Keepers and Dark Gods, as well as hostile heroes (unlike Wemos, for instance, who is a straight example).
The Faceless: We never get to see what Alphel really looks like, as when she's not possessing a creature, she's always in her dark alcove next to one of her dungeon hearts - leaving everything hidden except her red eyes. From the scenes of her talks with her minions (including her voice), it seems likely - though not certain - that she's large and monstrous.
Genius Bruiser: Like Morrigan, she also worships Azzathra, who's basically the Dark God of force, martial prowess and bullies, but Alphel is much more intelligent than Morrigan.
Villain Team-Up: With Arachne during their attack on Mercury's iceship. It didn't end well.
The Chessmaster: He tries to manipulate other Keepers into doing his bidding, and seems quite successful at it. Mercury tried to avoid dealing with Midori for as long as she could, but she eventually had to relent.
Enemy Mine: Repeatedly helps Mercury in her fight against Crowned Death's cult, as Midori himself is also on hostile terms with them.
Evil Genius: Possibly the single smartest Keeper in the world. Note: this is said while keeping in mind the other super-intelligent Keepers, like Ami/Mercury, Zarekos and Mukrezar.
Information Broker: As part of this job, he's very informed about the world, including current events. All sorts of news (guarded Keeper secrets included!) travels quickly to him.
Pragmatic Villainy: Midori doesn't shy away from making deals with goodly heroes and generally people who are unpopular in the Underworld, as long as it suits his goals.
Enemy Civil War: Was one of Zarekos' vampire minions who immediately after his death engaged in a free-for-all to gain control of his now unclaimed dungeon hearts and lesser undead.
Too Dumb to Live: His idea to gain power is to raid an Underworld city for supplies (needed because the Avatar Islands are completely dry). The smarter vampires in his employ immediately start jumping ship and heading off to join either Nero or Mercury, because they know that the plan is suicidal - the Underworld cities are not only fairly individually powerful, but also linked in a great web of mutual defence treaties. Even the greatest Keepers would get flattened should they attempt to take this alliance head on.
The Worm That Walks: Nero was human, but shortly before his real death after his forces are defeated by Mercury's he underwent the procedure he learned from Arachne, which killed his human body but allowed him to transfer into a 'body' made from thousands of insects - which is much harder to destroy.
Wasn't That Fun?: When Mukrezar returns, the Butler lists all the ways in which the Keeper put him in mortal danger and punished him unjustifiedly during his earlier service to him. Then he happily joins him, because despite all of that he had the time of his life!
Jerk with a Heart of Jerk: Underneath her beautiful elven exterior of a spoiled brat lies a core of unapologetic, petty evil.
Obfuscating Stupidity: Ami at first thinks Julia's just a horribly spoiled airhead. Horribly spoiled she is, but she's much more devious than she lets on at first (not to mention being KeeperMidori's minion).
The Berserker: Boris is all about attack, and relies on the endurance of his body rather than bothering to defend against blows.
Berserk Button: Keepers in general, due to what he experienced thanks to Mukrezar (see the Doomed Hometown line below). When he finds out Ami is a Keeper, he's perpetually either on the edge of exploding, or actually trying to kill her.
Doomed Hometown: Boris was born on the Avatar Islands, and witnessed their fall when he was a kid. He was one of the relatively few refugees who managed to make it out of there alive.
Dumb Muscle: He isn't exactly the brightest of people, which is also lampshaded by his companions. Couple this with stubbornness and traumas from his youth... and the result isn't a very reasonable man.
Badass Normal: When she was facing an impending duel with her first horned reaper, Ami mind-controlled the Baron for a bit (Strictly out of necessity! Honest!) in order to find out how he was able to fight the Reaper on equal terms. His answer? It wasn't any supernatural ability, but decades of constant training and improving his martial skills that made it possible. In other words, Baron Leopold is a perfectly normal human being... who is so good at fighting that he can best a horned reaper in combat! note Though to be fair, said reaper wasn't fit and was quite out of practice... but it's still a damn impressive feat!
Flat "What.": His cult, being necromancers, raise undead. This goes way beyond what people traditionally think of when they hear the term 'undead'... the weirdest (if logical) example being a raised coral reef. It's not threatening, as it moves very slowly (but it can move!)... still, seeing it made Ami pause.
Evil Genius: Just one example: when she captures Ami, the Unraveller starts immediately taking apart and studying all the items Ami has on her person. The speed at which the Unraveller perfectly figures out each bit of modern technology is scary. That's 20th-21st century tech in a medieval world!
Her body is big enough to have a horizon, with fractal micro-structure. And the tools/appendages used are described as suspiciously similar to a nanotech universal (dis)assembler.
Fragile Speedster: Outright states that, while she cannot match Azzathra or Crowned Death in combat, she can outrun them and thus doesn't need to fight them.
Kaiju: The God of Vermin seems to find much enjoyment and humor in the small vermin suddenly being able to squash the people, and is willing to give some followers (like Keeper Arachne) a spell to super size various critters.
Intrepid Merchant: Subverted. He may not care whom he does business with as long as he can turn a tidy profit, but he has a very keen survival instinct. He rather carefully appraises his clients, and acts according to how dangerous they are. He will most certainly not overcharge or disrespect a powerful keeper or heroic leader, for instance.