While many a character comes from the canon of Warhammer 40,000, the series gives them a... unique spin at times. Every spoiler up to Episode 25 (the last episode before the podcasts and spinoffs start) is left unmarked.
Cypher, Lord of the Fallen
- Voiced by: Verry
One of the most mysterious traitors of the Fallen Angels, a man who has eluded the Dark Angels for millenia and avoided capture ever since. He is currently plotting... something that involves a planet of ancient tech, the Mechanicus, and a free ride on the Dark Angels' ship. The reasons for this are currently unknown.
- Arch-Enemy: He is this for the Dark Angels because he is their most mysterious traitor. Ironically, despite being their most-wanted target among the Fallen, the Dark Angels don't recognize him and assume he's just another Dark Angel.
- Eating Shoes: He's been stuck in a desert planet for so long, one of the reasons he's glad the Dark Angels finally arrived is that he can "finally eat something that isn't fucking sand".
- Guns Akimbo: Wields a plasma pistol and a boltpistol as his weapons of choice.
- In the Hood: As with most members of the Fallen, he's sinister with that hood of his.
- Long Game: He's been planning something for millennia while on the run from the Dark Angels, to the point where their leaders seemingly don't remember what he looks like. Whatever it is, it seems to have something to do with the Dark Angels' natural-found paranoia, as he throws a book titled "The Secrets of The Dark Angel Chapter" at the Fabricator-General. When the Fabricator-General causes the Dark Angels to seriously reconsider how their trigger-happy cover-ups do more harm then good for their image, they immediately fall back to their old ways once they spot Cypher's book, leading to Asmodai to attack him under the belief that he's working with the Fallen.
- The Plan: He is planning something that may or may not aid or harm the Imperium. We just have no idea what it is yet.
- Refuge in Audacity: He infiltrates the Dark Angels by... walking right up to them and asking if they have any chips.
- Troll: Calls the Fabricator-General "today's prank victim," and throws a book at him that prevents the Dark Angels from having a Heel Realization, and seemingly kill him out of their usual paranoia.
- Squee!: Whenever nobody is around is around to see or hear it, he tends to do this when things go as planned.
An insectoid Xeno race from beyond the galaxy that has one single goal in mind for the countless planets they have come across — to devour everything in sight and to adapt and evolve in every possible way.
- Horde of Alien Locusts: Possibly the biggest one ever seen in fiction, due to how their full swarm is at least ten times bigger than the whole damn galaxy! Again; at least.
- Knight of Cerebus: The BEHEMOTH spinoff is Darker and Edgier thanks to them being its Big Bads.
- Throw the Dog a Bone: One of the less effective (and thus, rarely used) Tyranid units gets to kill a couple of Guardsmen during the BEHEMOTH finale, which makes it feel rather validated afterwards.
- Vile Villain, Saccharine Show: When these guys show up, there are very few laughs to be found. Even the daemons of Chaos are treated as a lesser horror compared to the Tyranids.
An extremely dangerous breed of Tyranid first encounter at the Battle of Macragge, leading their innovation, which nearly destroyed the Ultramarines.
- Authority Equals Asskicking: Commands Tyranid forces and is strong enough to easily best even accomplished veteran Space Marines like Marneus Calgar.
- The Comically Serious: What little comedy they offer comes from such seriously-played threats confronting the absurdity of the rest of the series's characters.
- The Heavy: When the Tyranids' Hive Mind needs to get shit done and its regular forces are not enough, it fields the Swarmlord to lead them and fight on the battlefield.
- It Can Think: Invokes this on other Tyranids by its presence, causing them to go from mindless beasts to being capable of tactics like faking death. The Swarmlord also proves smart enough to use Straight for the Commander and Flaw Exploitation (singling out Calgar, knowing he's too prideful to deny fighting it one-on-one rather than using all his available forces to kill it).
- Multi-Armed and Dangerous: Has four limbs wielding four massive swords capable of effortlessly cutting through Space Marine armor at blinding speed.
- Small Role, Big Impact: The Swarmlord at Macragge had only a single appearance in the series proper, defeating Marneus Calgar in a throwaway gag. BEHEMOTH reveals that this defeat led Calgar to do whatever made the Ultramarines the Parody Sue-level Comically Invincible Heroes they are at present, enabling the abduction and redemption of Magnus the Red and thus the Emperor's plan to reform the Imperium that is the driving force of the series.
Mephet'ran the Deceiver, the Jackal God
The C'tan known as the Deceiver, one of the most powerful among them all and definitely the most clever. Even in his weakened form he continues to plot and scheme behind the scenes, but it's become clear to him that current events call for drastic measures.
- Alien Geometries: Speaking to him requires unfolding what may be one of his shards, an unfolding cube that seemingly contains an entire dimension in itself.
- Animation Bump: He's a lot more animated than most other characters, with his model (especially the tendrils on his back) bouncing, twisting, and distorting with his movements. It fits well with his nature as an Eldritch Abomination.
- Big Bad: Of Special 7. Boy's balliterative betrayal and the subsequent stagnation of the galaxy happen due to his machinations.
- The Chessmaster: And one of the best at that. Even today he's not afraid to throw his own plans into the growing pile, coordinating the perfect moment to eliminate one of the biggest perceived threats he knows.
- The Corrupter: In Special 7: Space Game Pain, he convinces Boy to betray and declare war on the Emperor, giving him tons of resources (donated by Kitten's federation) to build a massive fleet and a planet-cracker for the purpose.
- Darkest Hour: He considers the current galactic situation to be at its most grimdark.Deceiver: State of affairs is actually what amounts to a collection of rocks desperately clawing their inanimate ears out as the organic shriek-machines are pulling them all STRAIGHT down the End Times pit. [...] Shit is flying left, right, up, down, nobody knows what the fuck is happening, but on, and on, AND ON they keep wailing their song of mutual destruction! 'Heretic!', 'Savage!', 'Upstart!', 'Lapdog!', 'LET ME EAT YOUR SPINE!', GAAAAAARGH! SHUT THE FUCK UP TAHRIL! You're part of the problem!
- Didn't Think This Through: His strategy of stagnating the game to hold off the End Times crisis events in Space Game Pain was doomed on multiple levels. First of all, Boy had already used Jump Drive tech, which is one of the crisis triggers. Secondly, the game is set up so the Bug War crisis fires by default if the others aren't triggered instead of having a trigger of its own. And third by ensuring the game was such a stalemate the "Not-God King Supreme" got so pissed off at the endless bickering that he used admin powers to spawn three separate crises at once to screw everyone over. By depressing everyone's economies all he did was make them less able to deal with it.
- Electronic Speech Impediment: When unpacked to speak with him, he "coughs" like a broken record and needs to clear his nonexistent throat before continuing.
- Faux Affably Evil: In Special 7, he speaks with superficial politeness, but when he gets called out on his actions, he begins ranting. Later, after the Crises wrecked his species, and Eldrad calls him out, his speech is full of venom.
- Foreshadowing: He makes a very brief appearance in Episode 25's intro in place of the emblem of Chaos Undivided.
- Go-Karting with Bowser: According to Tzeentch, he plays children's card games with Tzeentch, the Laughing God, and the Emperor regularly. In Special 7, he participates in a game of Stellaris that includes Eldrad Ulthran and the Emperor.
- Horrifying the Horror: In Special 7, he has a quick conversation with Boy as part of his plan to keep the setting in metaphorical stasis. His first line as soon as he closes communication is "holy crap, [Boy] is terrifying".
- Ice-Cream Koan: Not quite koans, but he has a certain flowery, metaphor-choked way of speaking that can get confusing. The general gist of what he says can however be easily picked up and he's thankfully aware enough of the current problem's seriousness to clarify if pushed.
- Leitmotif: The Deceiver has his own theme song in the form of the Jackal God.
- Mood-Swinger: To the point the show's Limited Animation deigned to give him actual facial expressions. In one conversation he quickly swings between Affably Evil smarm, annoyance brought from superiority and pure, frustrated anger back and forth.
- Most Definitely Not a Villain: In Special 7: Space Game Pains, the Deceiver goes to great lengths to describe himself as being incredibly nice and not at all suspicious, to the point of naming his in-game empire "The Trust of Trustworthy Fellows".Salutations, other species! I am known as "the Trustworthy", AKA "the Reliable", AKA "the Undeceiving", AKA "the Very Nice Creature That Wants To Trade With You"!
- No-Nonsense Nemesis: To Kaldor Draigo, even if the latter is probably not aware of it. The threat of his return is the only thing that'll get him off his trollish jokes and godly smugness, and he makes sure to be as clear as possible that he's not fucking around this time.Tahril: You know, you're saying a lot without saying much... so, you're planning on killing Kaldor Draigo?Deceiver: He cannot be allowed entrance to the materium again! No way! It CANNOT happen! It would spell DISASTER for my galaxy, Tahril! His screams will overpower ALL! Do you hear me Tahril!? LISTEN HERE, YOU KNIFE-EARED LITTLE SHIT! KALDOR DRAIGO MUST. BE. STOPPED!
- Not-So-Well-Intentioned Extremist: He spends the Stellaris game stirring up galactic conflict so that the game world will stagnate and stave off the End Times. Kitten promptly shows that hes capable of progress without destroying everything. He also mentions he only does this to prevent end of his galaxy.
- Pragmatic Villainy: He wants to prevent the destruction of the galaxy, but not for altruistic reasons.
- Suddenly SHOUTING!: As part of his Mood-Swinger trait, he will be talking smoothly one moment and THEN SHOUTING AT THE TOP OF HIS NON-EXISTENT LUNGS! the next, in order to gets points across.
- Status Quo Is God: Actively enforces this in the Stellaris special, where he keeps the galaxy stagnant to prevent any player from getting to the point of triggering an endgame crisis. Also delivers an almost fourth-wall breaking speech on why it is better to do this and keep the setting open for many potential stories rather than risk advancing (and eventually ending) it.
- Troll: Perhaps the biggest in the galaxy. He's screwed over his fellow C'tan before and had a mighty good laugh about it, and even when speaking with his subordinates he's not above jerking them around.
- Wild Card: He's not really on anyone's side except his, which he claims is the side of "his" galaxy as a whole. Tellingly, while everyone else's plans are in favor of their own side or against another, his own is almost entirely perpendicular to any of their goals, and its purpose is to protect the entire galaxy from and eliminate Kaldor Draigo, who he believes would end up destroying it.
- In Space Game Pain, he spends the entire Stellaris match manipulating and sabotaging the other players, crippling the galactic economy, and otherwise making sure the game becomes stagnant, all to stave off the late-game and prevent anyone from triggering the crisis scenarios.
The galactic empires created in-universe for Special 7.
The Bellyscratch Coalition of Good Lads
Kitten's empire, an egalitarian, xenophile, pacifist federation and pretty much the only ones who don't engage in constant war.
- Boring, but Practical: Their strategies of equal rights, peaceful trade with neighbors, and conserving military power instead of indulging in pointless wars ultimately leaves them the last empire standing. Rogal Dorn declares the trope almost verbatim, as a bitter insult, and everyone else agrees.
- Curb-Stomp Battle: Thanks to their utterly enormous home fleets, they manage to stay more or less on top of invasions from the Triple Crisis.
- The Good King: Kitten, by virtue of providing peace, protection and plenty to his subjects and haven to his embattled neighbors.
- Irony: The BCoGL is pretty close to (an idealized/optimistic version of) the Tau Empire. It's created and ruled by Kitten, who hates them with a burning passion.
- Naïve Newcomer: They're kind and outgoing, welcoming any outsiders into their empire, which serves them poorly in a galaxy where the mightiest empires enjoy killing aliens for kicks. Miraculously, they make it work and come out on top.
- Number Two: The leader of the Empire (aka Kitten) is served primarily by Sir Science (Santodes) and Kockstodes (Karstodes).
- No-Sell: They manage to do this to three end-game crises at once, the most powerful of which spawned directly at their border!
- Only Sane Man: As Kitten puts it, they're the only ones who don't engage in war every five minutes, resulting in them having the most resources and ships in the endgame despite the Undeceitful's sabotage of the galactic economy.
- Science Hero: Sir Science, the empire's lead scientist (aka Santodes).
- Sole Survivor: The Coalition is the only empire to survive the Triple Crisis, which leads to Kitten winning the game by default once the final in-game year rolls around.
- Utopia: They are built around utopian ideals, and manage to stick to them in spite of the galaxy burning around them.
The Supreme Kingdom of Humanity
Big Emps's empire and his vassals, more or less recreating the Imperium as it was during the Great Crusade.
- Absolute Xenophobe: Downplayed, compared to the real Imperium of Man, in that certain alien races are shown to be accepted as vassals (Prime Mineral Rogus's lithoids and Boy's molluscoids). However, first contact with new empires is anything but peaceful.
- Dystopia Is Hard: The Emperor freely admits that part of the "power fantasy" Eldrad accuses him of indulging in is the fact that he can now micromanage every aspect of his galactic empire. However, this doesn't stop him from eventually losing interest in his military campaigns and delegating responsibility to his vassals while he messes around, with predictable results.
- Evil Counterpart: On Stellaris's Ethos spectrum, they are the polar opposite of the Bellyscratch Coalition — militarist, authoritarian and xenophobic. In addition, the Not-God King Supreme's allies are his empire's vassals, as opposed to Kitten running a federation of independent states.
- History Repeats: The Not-God King Supreme promotes Boy to "warmeister" and carelessly delegates responsibility to him, so he can mess around back in the core systems. This results in Boy being manipulated by the Undeceitful and starting a bloody civil war. In the end, the Not-God King Supreme confronts Boy aboard the latter's capital ship, and they destroy each other. Rogal Dorn is quick to complain about his Trauma Button being pushed in the aftermath.
- Nerd in Evil's Helmet: The Not-God King Supreme's most powerful military vassal turns out to be none other than Boy, clad in a massive, dark-colored suit of armor with a Horns of Villainy and Glowing Eyes of Doom.
- Rage Quit: After Boy blows up his homeworld and ruins his aspirations of galactic conquest, the Emperor disconnects from the game and leaves his empire to balkanize. When his attempt to rejoin the game is prevented by the Undeceitful sending Marauders to destroy what remains of the Supreme Kingdom, the Emperor not only quits again but uses console commands to completely derail the campaign out of spite.
- The Remnant: The empire quickly shatters, turned into Boy's Bulbous Bempire, REJGIBHPWERUGIWEHB note and Rogus' Empire.
- Rocks Fall, Everyone Dies: The Not-God King Supreme eventually gets fed up with the game and uses console commands to trigger the late-game crisis events early and simultaneously, plunging the galaxy into chaos.
- The Starscream: Boy becomes this when he, with the help of the Undeceitful, tries to usurp the empire.
- Succession Crisis: Of a kind. After Boy turns against his father and the Not-God King Supreme fucks off to harvest on a moon, the Empire is split between his three heirs. Ironically, Boy, the most ambitious, gets the smallest portion of his father's empire.
The Trust of Trustworthy Fellows
The Undeceitful's Empire. While one of the largest empires in the game, the Undeceitful seems content to just help out his allies. Surely this kindly and trustworthy fellow has no ulterior motive whatsoever.
- All for Nothing: The Undeceitful's attempts to forestall the Endgame Crises fails spectacularly when the Not-God King Supreme triggers all of them at once via console commands. The implied game mechanics also suggest that even if that hadn't happened, the attempts still would ultimately have failed. note
- The Chessmaster: The Undeceitful manages to cause most of the crap that goes down in the galaxy by convincing the Coalition-led federation to supply him with tons of resources to solve their problems with the Space Crusaders.
- The Dragon: The Undeceitful has one in the form of Vulk-Gon, the Hugger of Worlds — a marauder warlord he hires to ransack the fractured Kingdom of Humanity, in an effort to prevent the Not-God King Supreme from returning to the game.
- Necromancer: The Trust's military apparently consists entirely of undead, and at least part of the Undeceitful's motivation for instigating the Forever War is to ensure he never runs out of corpses to collect. According to Sir Science, by the time the game ends the Trust's armies include entire species of minor races rendered extinct by warfare.
- Number Two: Jeff is this to the Undeceitful. It's unclear if he's an ally or a vassal, but the Undeceitful doesn't seem interested in conquering his territory, and they work closely together.
- Obviously Evil: No duh, he does not strike a trustworthy figure. Despite his insistence otherwise.
- Suspiciously Specific Denial: When he meets Kitten, he calls himself "The Undeceitful" (along with '"The Trustworthy", aka "The Reliable", aka "The Very Nice Creature That Wants To Trade With You"') and shouts "YEEEES, I have NO ulterior motives" unprovoked.