Bestiary of BTVS
Angry Mobs: The mobs on BTVS are like mobs in the real world. They can't be reasoned with or controlled and will destroy anything in their way. In BTVS however, they are usually under a spell of some type(can you say, "Love spell?").
Extermination: They are hard to calm, so it is best break the run away. While running away, finding a second mob and letting the two fight each other is a good way too. It is probably best to break whatever spell they are under though.
Ghosts: The undead spirits of BTVS seem to be evil, but are basically misunderstood spirits (and Willow transformed on Halloween does not count) trying to get some type of closure, often by killing people. Its approach depends on the ghost's personality and situation. Some ghosts are around to torment the people who did them in or people like those who caused them pain.
Extermination: You can try to ward them, but that tends to bring up hordes of wasps or deadly flying objects. The best way is to give them the closure they are looking for, or you can stab them with their own ancient weapons when they transform into a bear.
Initiative: A secret group of humans on the campus of UC Sunnydale. They capture and experiment on various demons. The Initiative seems to be government funded, and it appears that its commandos are being feed chemicals to be super-human. So far the Initiative has been able to "human safe" vampires, and create Adam from parts of demons, humans, and machines. They have an underground lab beneath a frat house that has a Pitt, containment cells for Hostile Subterrestrials, and places for experiments.
Extermination: The members can be killed like normal humans, though evidence is reveals that some members were more than human. However, the complex was closed down by the US government after Adam let all the demons out to kill the Initiative members.
Robots: There are no friendly robots appearing on the show as of yet. They are just plain bad, containing the spirit of a demon or are programmed to kill their wives over and over again.
Extermination: Electrocution does the trick. Also beating one to death with an iron skillet after stabbing it with a nail file.
The Scourge
It's a huge group of pure blooded demons that look suspiciously like football heads are on a quest to eliminate all half-breed demons. They are a big legion and are willing to die for their cause. Expect big things from them!
Extermination: More physical violence will get rid of them, if you can kill them all.
Vampires: (Since there is so much to say about vampires, this section is divided into several mini catagories) The (duh) main enemy in BTVS are basically dead human bodies with a demon living inside of them. While they do retain their human memories and personality, they come usually without souls. Vampires are made when a vampire drains the blood from a human and exchanges a small amount of its own blood with the dying human. The corpse will be buried and wake up as a new member of the undead. The new vampire is called a fledgling or minion, and it owes its allegiance to the vampire that made it, its sire. There is a whole clan and blood-tie system that has never been particularly clear. There are master vampires who can gain strength from the feeding of the minion designated as the Vessel, and have a great warrior called the Anointed One. Young vampires are notoriously stupid and usually are used as cannon fodder for the Slayer. The older vampires tend to be much more trouble and much harder to kill.
Physical: They appear to be normal people unless they are feeding, or if they have been unable to adjust with the changing times. Every vampire needs blood to live. Human is preferable, but they can reluctantly substitute it with pig's blood or some other animal. When feeding the demon must come to the surface, bringing forth the 'game' face (that ridged eye brow thing), fangs, and yellow eyes. Since they are walking corpses, vampire body temperature remains at room temperature and they lack circulation of the blood (yet they are still able to have sex). They don't need to eat food, but can get drugged, high, or drunk. They do not have reflections in mirror and do not appear on normal camera film because of that. Video cameras do not use mirrors so they can appear on video. True to legend, vampires cannot enter homes unless they are invited in. Afterwards they can enter whenever they want to unless the invitation is revoked by magic. Sunlight is deadly so vampires must remain under cover during the day. Fortunately for them in Sunnydale and LA, there is a huge underground tunnel system, perfect for hiding out.
Mental: The existence or lack thereof of real emotion by vampires is debatable. Angel was able to fall in love, but he had a soul. Spike was in love with Drusilla, on the other hand, though he did not have a soul. Other than these exceptions, the normal vampire is ruled by basic animal emotions. The vampires feel the worst of human emotions: anger, lust, revenge. The characteristics a human has when they are turned carry over into being a vampire (Drusilla was an insane psychic before she was a vampire and after.) Most vampires believe they are the top of the food chain and deserve to rule the world.
Extermination: There are several methods of getting rid of vampires. Staking through the heart is by far the most popular method. Vampires can be burned by holy objects like crosses, bibles, and holy water. Burning can also reduce a vampire to ash as does the sunlight. It has been theorized that lack of blood could kill a vampire, but it has yet to be seen. Garlic is poison for them, and beheading does kill them. They can be injured, but they heal remarkably fast depending on how injured they are. Vampires do not recover from being eaten by mother bezoars.
Holidays: The Harvest- the Master vampire could draw power from the feeding of one of his minions.
Halloween- It's a quiet night for the super-natural unless you decide to make a deal with a magician.
Night of St. Vigeous- Started by St. Vigeous leading a vampire crusade through Russia, Persia, and elsewhere, it is the night at which vampire power is at its height. If you're impatient like Spike, attack early and try to catch the slayer by surprise. (Watch out for her mom!)
A Moon day: There is some confusion on exactly whether it occurs on the night of the full moon or the new moon. Either way, on this day it is possible to revive an ailing vampire with the blood of his/her sire.
Important vampires(dead): The Master, Luke the Vessel, Collin the Anointed One, Dalton the smart vampire, Mr. Trick, Tector Gorch, Kakistos, Candy Gorch
Important vampires(alive): Angel, Spike, Drusilla, Harmony, Lyle Gorch, and Darla *Just brought back from the dead!*
Watcher Council: This group of so-called humans are supposed to be monitoring and training all girls that are potential slayers, at least when they can find them. Watching does run in families with Giles the most recent in a long line of Watchers. They keep meticulous records of a slayer's exploits, but their memos seem to get lost easily. However there seems to be some internal strife somewhere within the organization. They tend to attempt to give their slayers orders, but in Buffy's case, she attempts to ignore as many of the stupid bigoted orders she receives. In fact, both she and Giles no longer participate in the council. The council does have yearly Watcher retreats, and it has is own special forces team which turns out to be no match for a renegade slayer. Also on a Slayer's eighteenth birthday, they have the Watcher take away the slayer's powers so she will get stronger by surviving without them. Overall just a cryptic group whose motives get more questionable by the episode.
Extermination:They can be killed like normal humans, unless you are evil Ms. Post and will therefore be killed when a shard of glass forces the Glove of Myhnegon.
Werewolves: They look human, most of the time, except for those three pesky nights of the full moon. During that time they transform into super-strong, super-uncontrollable humanish wolves. The debated is still continuing on who is in control while the werewolf is not in wolf form, the human or the wolf. While in human form, the werewolf does retain a heightened senses of smell, and as the full moon approaches, all the werewolf's senses get keener. Whether they are good or bad depends on the personality of the human because they control where they are before they transform. Say, in a cage, as opposed to wandering the night killing people. To become a werewolf, one must be bitten by a werewolf. There is no cure for being a werewolf, also known as lycanthropy, so avoid the Initiative and crazy hunter guys.
Extermination: Anything with silver can do it. To just take one down tranquilizer darts are good. Massive physical damage can kill one too, like having your throat ripped out or getting shot in the spine.
Witches/Warlocks: They are humans who have access to magic powers. Magic does tend to run in families, but it is not a prerequisite to be a witch or warlock. Much of their power comes from his/her spells which usually need strange materials and chanting. Praying to various gods and goddesses, chanting, and casting spells or hexes is typical witchy fare. The will of the spell-caster is important because he/she are able to move objects and do other spells by simply thinking about it. Covens (several magicians working together) are able to do bigger and stronger spells than single witches. It does seem that magic is rather chancy with lots of room for mistakes. A bunch of various spells have been seen on BTVS, ranging from transformation, body switching, possession, demon raising, love spells, soul addition, pencil floating, ionization, vengeance spells, spontaneous cheerleader combustion, voodoo stuff, astral projection, and the list goes on.
Extermination: Kill them like normal humans.
Important people (dead): Jenny Calendar, Catherine Madison (in a trophy)
Important people (alive): Willow, Ethan Rayne, Amy Madison, Rupert Giles
Wofram and Hart: A group of mysterious lawyers that have clients in all sorts of supernatural circles. They have lots of power, their hand in lots of crime, and kinda remind one of the Firm. Their business tactics are just slightly cut-throat, and they have no qualms about eliminating those who get in the way. They appear multiple times throughout Angel.
Extermination: The owners have never actually been seen to know how to get rid of them. The lawyers however can be killed by any normal human means, we've seen the use of a gun and a sword so far. For more information the firm's clients, see Angel's Encounters.
Zombies: The literal walking undead. Not a lot to say about them since they don't have much personality. Hey, they're walking corpses, what did you expect?
Extermination: They can't die, since they are already dead so they are kinda indestructible, but you need to take out whatever is giving them power, like a Nigerian death mask. Incidentally, don't look into the eyes of the mask or it will paralyze you. Also, being decapitated or eaten by a Hellmouth demon or werewolf severely slow them down.
Bringers/Harbringers: The nice friendly guys also known as the Priests of the First who are trying to raise the First Evil. They don't have eyes, nothing can grow above or below them.
Extermination: Cut off their heads.
Episode: Amends
Gruenstahler Brothers: These were hunters participating in Slayfest '98. Not particularly smart, the two use lots of technology with guns and tracking devices.
Extermination: They can be killed like any normal human, but make sure they don't shoot you first.
Episode: Homecoming
Invisible People: They occur in high schools were certain people are ignored until they actually become invisible. Be careful about them because they seem to resent the people who ignored them. It seems the invisible people are employed by some type of government agency to be used as spies.
Extermination: They can be killed like normal humans, assuming you can find them.
Episode: Invisible Girl/Out of Sight, Out of Mind
Lunchlady: A good school employee gone postal, she tries to kill all the students of Sunnydale by spiking the food with her own rat poison cocktail.
Extermination: Physical violence because this problem won't be solved by talking.
Episode: Earshot
MOO: Mothers Opposed to the Occult are being controlled by the Hansel/Gretal demon to get rid of witches. See the Angry Mob category.
Mummies: Usually imprisoned by containment seals, if the seal is broken, the mummy will awake. The mummy can only survive by sucking the life out of other creatures through kissing.
Extermination: Reassemble the seal, and don't let the mummy get any new energy, so it will shrivel up to a boring old mummy again.
Episode: Inca Mummy Girl
The Slayer: A second slayer was created when Buffy died during Prophecy Girl. Kendra was killed so Faith was called to take her place. Originally on the good team, Faith traded her allegiance to the Mayor and had to fight Buffy. After Buffy put her in a coma for eight months, Faith switched bodies with Buffy for a while. Somewhat haunted and psychotic, Faith is currently in jail after visiting Angel in LA to turn herself in.
Extermination: Kill her like any other normal human. Stab wounds to the stomach only kept her down for eight months.
Ugly Man: A projection of the fear of a comatose young boy's little league coach which causes Sunnydale residents to receive nightmares featuring their worst fear.
Extermination: A simple cure, find the cause of the nightmares while you sleep, confront the fear, and bring the cause out of his coma. (Freddy Kruger anyone?)
Episode: Nightmares
Alcatha: This squarish yellow demon was turned to stone when stabbed by a 'virtuous knight.' However when someone 'worthy' pulls out the sword, in addition to the wackiness that will ensue, Alcatha's first breath will open a vortex that will suck the world into hell. Pulling the sword out involves a long ritual using the blood of the worthy one.
Extermination:You can't. It can only be contained by stopping the ritual from occurring or by spilling the blood with the special sword of the one who opened the portal to Hell and sending him to Hell.
Episode: Becoming Parts 1 and 2
Balthazar: A really ugly fat demon that vampires called Eliminati attempt to take care of. He was killed at least once previous and is searching for his amulet so he could use its power to defeat the demon that will rise at the Ascension. Balthazar was crippled 100 years back despite his telekinetic powers.
Extermination:Electrocution or whatever the other demon did to him.
Episode: Bad Girls
Chaos Demons: Never actually seen yet, though Spike assures us they are all slime and antlers. They must have mouths though if they can kiss.
Extermination: Not a clue, never been seen.
Episode: Lover's Walk
Eyghon/Etruscan Demon: An Etruscan demon can possess the unconscious/dead bodies of people. Raised by Giles and friends, Eyghon hunted down those bearing his mark. When he leaves a dead/unconscious body to move into another, the original body dissolves into purple slime.
Extermination: Find a vampire, let the vampire nearly kill the current host, force Eyghon to jump into the vampire, and calmly wait as the vampire's demon finishes off Eyghon.
Episode: The Dark Age
Fyarl Demon:Big brownish two-horned demons like this are usually pretty slow. While incredibly strong, according to Spike, their best weapon is the paralyzing mucus they can shoot out of their noses.
Extermination: Slay them with any silver object.
Episode: A New Man
Fungus Demons: Another never seen demon that was mentioned by Spike.
Extermination: Not a clue, never been seen, but Drusilla is currently with one.
Episode: The Harsh Light of Day
Gachnar/Fear Demon: Demons that when summoned partially are able to make people's fears come true. Their fear causing abilities are much more fearsome than their six inch size.
Extermination:They're six inches tall. Stomp on him!
Episode: Fear Itself
Hans/Gretta Demon: This demon appears periodically as two dead children. It attempts to get MOO (Mothers Opposed to the Occult) to burn the 'witches.' When trouble starts the children combine to form one big ugly demon.
Extermination: After forcing in to reveal itself with magic, staking with the pole you are tied to works just swell.
Episode: Gingerbread
Hell Hounds: More ugly low level monsters that like to kill and feed on human brains. They aren't very smart but can be trained to kill specific types of targets.
Extermination:The three S's seem to work: shooting, stabbing, and strangling
Episode: The Prom
The Judge: A big blue unkillable demon who can literally burn the humanity out of people. Was once cut to pieces and buried in separate spots by an entire army. Therefore, especially now, some assembly is required.
Extermination: Rocket launcher
Episode: Innocence and Surprise
Kathy/Annoying Roomate Demon: Some demons must really want to get an education. This one pretended to be human by hiding its ugly face behind a mask. Its fellow demons wanted it to return to its home dimension, so it tried to steal its roommate's soul. Some signs you roommate my be a Kathy are an obsession with Celine Dion and Cher, toenail clippings that don't stop growing, and scary dreams where your roomate tries to suffocate you.
Extermination: Once her skin was peeled off, and it became apparent the soul was not surrendered, other demons came to get her.
Episode:Living Conditions
Kulak/Meequi clan Demon: A demon that participated in Slayfest '98. It had a big spiny head and was quite happy to help hunt down the Slayer.
Extermination: A hand grenade seemed to do the trick, so I'll guess fire is a good final solution.
Episode: Homecoming
Laconsis: A big ugly snakelike demon living in the Sunnydale sewer system that needs to be given a human sacrifice every thirty years.
Extermination: Fire and lots of it.
Episode: Band Candy
Lagos: Yet another big brutish demon that can throw slayers around with relative ease. Searching for the Glove of Myhnegon which appears to be able to throw lightning, it meets its match.
Extermination: Beheading with a sharp object.
Episode:Revelations
Lohesh: A four winged soul-killing demon mentioned by Anya that once Ascended. It destroyed the town in hours, leaving three people alive.
Extermination: Unknown, though it would be vulnerable after the Ascension
Episode: Graduation Day Part 1
Machida/Reptile Demon: These demons are able to grant financial success if you are willing to give it human sacrifices as offerings.
Extermination: Cut it in half with a sharp object. This will destroy all the financial success for the disciples.
Episode: Reptile Boy
Marc the Demon: There are some demons that renew their life by collecting organs every seven years. They need a heart and a brain for sure.
Extermination: Stabbing through the heart is good.
Episode:The Puppet Show
Moloch the Corruptor: A horned demon that is trapped in books that must be read to summon him. Preying on impressionable minds from the computer, he was able to kill a few students. He was able to get out of the computer and appear as a robot.
Extermination: Trapping it with an ancient spell, works to stop it in its tracks. Then electrocution can take care of the tin body.
Episode:I, Robot. You Jane
Olvikon: The demon the Mayor is changing into. Its a huge giant snake that eats people and can shrug off tons of damage.
Extermination: Either volcanic eruption or a giant bomb in the school.
Episode: Graduation Day Part 2
Order of Takara: An ancient order of bounty hunters dating back to King Solomon's day that can be hired to hunt down and kill a target. They can be identified by the rings they wear. Only three of the assassins have been seen so far; so there are probably more we haven't seen yet. One short-lived big man was identified by a cyclops. The bug man masqueraded as a cosmetics salesman and was identified by the worm. The other one, jaguar woman, was pretending to be a police woman on career day.
Extermination: First one was taken out by partial decapitaton with an ice skate, we'll assume any sharp object will do. The second one, bug man, was killed by being glued to the floor and stomped to death. The third one, the police woman, was buried under the church and is presumed dead, so let's say beating with a blunt object.
Episode:What's My Line Part 1 and 2
Polgara Demons: Relatively stupid demons characterized by the bone skewers growing out of their arms.
Extermination: They can be trapped easily with nets. Though we don't actually see them get killed, their arms can be cut off and sewn on others
Episode: The I Team
Sisterhood of Jhe: These female demons are try to open the Hellmouth and like to eat the bodies of those they kill. They manage to raise yet another unnamed demon from the Hellmouth.
Extermination: Spells to lift the fog and then slay them with a sword.
Episode:The Zeppo
Vengeance Demons: These demons dwell on a different plane and are made to grant vengeance for people. They can appear in nearly any form, so far just Anyanka, the saint of scorned women, and her creator D'Hoffryn have been seen yet. Their power is derived from their necklaces, losing one or destroying it will trap the demon in whatever form it is currently in. They are created when D'Hoffryn hears the pain of a scorned person and offers a vengeance demonship, which she/he may choose to accept.
Extermination:Break the necklace and then you can kill them in whatever form they are in.
Episode: First seen in The Wish and play a big part in Something Blue
Whistler: A demon sent by the Powers That Be to even the score between good and evil. A short guy with weird clothes, he was just a little cryptic in his foretelling of the future.
Extermination:Why would you want to do that? Unknown.
Episode: Becoming Part 1 and 2
Der Kindestod: Also known as child death, it kills children by sitting on them and sucking out their life-force. While invisible most of the time, it is visible to children or those with fevers.
Extermination: Once you find it, (you have to have a fever) you can break its neck. That is if you aren't to weak from the fever.
Episode:Killed by Death
Fishpeople: They are made when someone mixes human DNA with fish DNA through steam. Its quite appetizing because the host splits out of his skin and turns out to be a scaly fish person underneath. They are quite violent and like to eat human flesh.
Extermination: Not sure, take them out of water? The last set was seen heading out to sea.
Episode: Go Fish
Gavrok Bugs: These are the bugs held in the Mayor's box of Gavrok. There are about 50 billion of them, and they are to be eaten by the Mayor before his Ascension.
Extermination: Squash them!
Episode: Choices
The Gentlemen: Very, very scary, that's for sure. The tall pale guys have come to collect the hearts of people and rob them of their voices. They have little Igor-like assistants helping them with the cutting out of the hearts. They keep all the voices in this little box.
Extermination: Human screams do it every time. (Their heads explode)
Episode:Hush
Hyena Spirits: Also know as the Pack. The hyena spirits posses people who step into the mystical circle, forcing the victims to act on animal instinct. When the Pack was at Sunnydale High, Herbie the pig, Sunnydale's mascot, was eaten (by the Pack with Xander) and so was Principal Flutie (without Xander).
Extermination: Feeding the possessed to real hyenas works, though I recommend you perform the ritual that puts the spirits into an evil target before doing this.
Episode: The Pack
She-mantis: These monsters are able to appear in human form though they are still able to twist their head around all the way. She-mantis search for virgin males to have sex with before snapping off the male,s heads.
Extermination: Bat sonar is able to scare them, and bug spray does hurt them. If you want to kill one, a big sword and lots of chopping will work.
Episode: Teacher's Pet
Bracken Demons Blue-green demons with spikes coming out of their heads are able to inbreed with humans. They are stronger than humans, they have a good sense of smell, instinctive ability to not get lost, and they are pretty good at basketball.
Extermination: Physical violence can work. Doyle doesn't count since he was killed because he was half human.
Episode: First appeared in City of Angels.
Burrower: An appetizing breed of demon that moves from body to body through sex while looking for the perfect mate. This body moving kills the original carrier, but gives the current carrier incredible strength.
Extermination: Physical violence can work followed by serious flame treatment.
Episode: Lonely Hearts
Caliph Demon: Seen only in one episode, these guys are willing to lend out their money to others. However they do want it back and are willing to kill to get it back.
Extermination: Again the answer is physical violence, weapons are not necessary.
Episode:Rm W/ A Vu
Dr. Ronald Meltzer: The good doctor has a lovely talent of being able to detach and control pieces of his body. The main uses of this talent fall into the stalking category.
Extermination: Chop off his head.
Episode:I Fall to Pieces
Empath Demon: Nearly human looking, except for the ridges, empath demons are able to sense the emotions of those around them. While we only have a small sampling, it was rather ruthless and violent, which could have been only that demon. He enjoyed causing pain that he could feel.
Extermination: Stabbing with a Kungai demon horn works.
Episode:Parting Gifts
Ethros Demons: Apparently able to posses people, they practice in soul-stealing, but do not like to live in bodies without souls. Exorcising an Ethros is very dangerous because when it comes out it flies to the nearest living body, usually killing it. You can catch it in an Ethros box.
Extermination: First you need to get it out of the body it is possessing. To do that you must perform a ritual and catch it in an Ethros box. A Shoreshack box works except it is alittle too small. Once without a body, and Ethros can be killed by a sharp object or plain old violence.
Episode:I've Got You Under My Skin
Fight Demons:
The demons appearing here are many, many, many and very unspecific because there are so many different unnamed types. They aren't actually bad, most of them, just unlucky enough to get caught and have to fight 21 times for freedom. Incidentally that is not a problem since they are currently running around free on the streets of LA.
Extermination: Fighting with fists or weapons seem to do them in.
Episode:The Ring
Impregnating Demon:
This lovely demon has human men impregnate women with his seed to procreate. The babies grow pretty quickly, communicate telepathically with their mothers, and are able to make their mothers drink blood. The huge grown demon is invulnerable to fire and cannot be decapitated.
Extermination: The easy to acquire liquid nitrogen bath is good.
Episode:Expecting
Jheria/Tae: Demons from another dimension, the males keep the women as slaves by removing their spines to 'unmake them.' Several of the women have escaped into our world and have the power of fire in their bodies. The males are constantly pursuing them, trying to unmake them and kill the female resistance.
Extermination: Burning and probably physical violence.
Episode:She
Kungai Demon: A single horned Japanese demon, their horns are what keeps them alive. There is probably some type of magic in it.
Extermination: Cutting off the horn leads to a slow painful death.
Episode:Parting Gifts
Kwaini Demon: These mummy wrapped demons are supposed to be peaceful and gentle. However when they are high on thyroid stuff, they become rather uncontrollable.
Extermination: If it's high, you'll have to beat it to death
Episode:The Prodigal
Lister Demons: Demons with funny brown and green scaled faces. Though we have only seen the half-bred form, they appear to be peaceful.
Extermination: They can be killed like normal people, we assume.
Episode:Hero
Maura Demons: A bunch of green ninja demons with jewels in their foreheads. Their blood regenerates dead tissue, which is cool.
Extermination: Hit the jewel in their forehead.
Episode:I Will Remember You
Restaurant Demons: Look, I know they have a real name, but I can't remember it. I also taped over that episode of Angel by mistake. Either way, they are civilized red demons who own a chain of expensive restaurants. They don't follow many old traditions except the one where you eat the brains of your fiancee's ex-husband.
Extermination: I'm thinking physical violence and sharp objects, but we never actually saw one get killed.
Episode:The Bachelor Party
Tentacle Demon: All you need to know is that its big, it lives in the sewers, and cleaning up after it is gross.
Extermination: An enchanted sword should do it.
Episode:Sense and Sensitivity
Augmention Moster: Created by Jonathan, this monster is the bad half of everything wonderful in Jonathan. The more perfect Jonathan was the more evil the monster was. Killing it or injuring it made Jonathan more normal and less perfect.
Extermination: Beat it up and throw it down a hole.
Episode: Superstar
Axe-wielding Demons: Several of these demons have been captured by the Initiative and are used to eliminate possible threats.
Extermination: If you have weapons, they die by sharp objects and electrocution.
Episode: The I Team
The First Evil: The Bringers are trying to raise it. It cannot be fought because it is not a physical force and can appear in any form it wants. It is like an absolute unstoppable evil, using your shame and fear against you.
Extermination: Resist it and conquer the fears it feeds on in you. Killing the Bringers helps.
Episode: The Zeppo
Ken/Dimensional Demons: These demons run a human slave ring in the netherworld were time passes very quickly. They force humans to work in huge factories.
Extermination: It would appear that stabbing, axing, and beating to death with a blunt object can take them out.
Episode: Anne
Master's Monster: Apparently one of the many monsters living in the Hellmouth, it occurred only when the prophecy predicted by the Pergamum Codex in which the so-called apocalypse is supposed to happen. Rises from the Hellmouth in the library. Possibly what the demons in Doomed were trying to raise. (Or one of the many others)
Extermination: Kill the master and it will disappear. In Doomed, don't let the demons complete the ritual.
Episode: Prophecy Girl
Pete: The Mr. Hyde in a relationship, drinking this green potion transforms the drinker into a big mean jealous version of himself. The mean version is strong enough to fight werewolves and vampires, and is able to kill easily with his bare hands. Originally the potion was supposed to make him more macho, but soon he was able to make the change without the potion.
Extermination: Physical violence all the way. Vampire bites work.
Episode: Beauty and the Beasts
Scabby Demons: These demons are ugly brown guys without mouths because they communicate via thoughts. They can infect those who kill them with their psychic powers through their blood, which can drive them insane.
Extermination: Their hearts can be cut out and drank.
Episode: Earshot