Although only demon halflings are referred to as “halflings,” the term can refer to any being that was human before his or her transformation. Neither humans nor halflings are susceptible to the paralyzing effects of hellhound venom. The transformation of a human to any other being must be voluntary. A vampire forced to transform can recover, but typically dies; a human can’t be forced to become a Guardian or demon halfling.

Guardians

If a man (or woman) is mortally wounded or dies while saving another’s life or soul from a demon, nosferatu, or vampire, the Doyen offers him a choice to become a Guardian. A Guardian’s natural appearance matches his human appearance. Guardians can shape-shift. They don’t eat or sleep. Their wings are white, although they can look like demons or nosferatu, if they want. Fast and strong, they quickly heal and are immortal, but they aren’t indestructible. They can be killed, or if they choose to, they can Fall or Ascend. If they don’t have a teleporting Gift, they must use the Gates to travel between Caelum and Earth.

Gifts: Every Guardian receives a Gift with his transformation — an extra ability. A Gift often reflects some aspect of their human life, for bad or good. Teleporting, healing, manipulating metal or locks, pyrokinesis, detecting Truth, and predicting the future are all Gifts that we’ve seen in the series, but there are many more.

Novices: Typically, a Guardian’s first hundred years are spent training in Caelum. During this time, the Guardian is considered a novice. Every novice has a general instructor, a mentor who is highly skilled in many disciplines; toward the end of the hundred years, he begins his weapons specializations, and trains with an expert in that particular form of weaponry.

The Doyen: The Guardian who transforms humans and enforces the Rules among the Guardians. Generally, the Doyen is the strongest of the Guardians and accepted as the Guardians’ leader. The Doyen also reverses the transformation when a Guardian Falls, and obliterates the Guardians who Ascend.

Falling and Ascending: When a Guardian chooses to Fall, he reverts to his human form and begins aging again. Falling leaves its mark in the form of a longer life and greater-than-typical strength, but the depth of the mark depends on how long the human was a Guardian.

If a Guardian chooses to move on to his afterlife, he Ascends.

Psychic abilities: A Guardian can sense emotions from anyone who doesn’t have psychic shields and receive projected images. A Guardian cannot read thoughts. They have a psychic storage space known as a cache or hammerspace that can hold anything that isn’t alive and that they can wrap their mind around.

Demon halflings

Demon halflings are created during a ritual sacrifice, during which a bargain is made to serve Lucifer, symbols are inscribed in the human’s body, and the human then ingests the blood spilled before he dies. Strong and fast, they do not sleep or eat. They can shape-shift (they cannot take animal forms). Although its natural form is the human form, to avoid Lucifer’s wrath, the halfling typically adopts a demon’s form in Hell: genderless, skin made of red scales, leathery wings, and cloven feet. Black horns curl back from its forehead. Demon halflings can travel to Earth through the Gates.

Unlike demons, who do not have a sexual drive and cannot experience arousal, halflings possess all the emotions of a human. They typically do not show human-like emotions, however, to avoid angering Lucifer.

The Symbols: A halfling’s strength and abilities can be altered if the symbols carved into her body are changed. This is typically done as punishment.

Psychic Abilities: If someone does not have psychic shields, a halfling can read his emotions. A halfling can receive projected images, but not articulated thoughts. Some halflings, granted the ability by Lucifer, can influence human dreams. They have a psychic storage space known as a hoard (a.k.a. cache, hammerspace) that can hold anything that isn’t alive and that they can wrap their mind around.

Strength: Halflings are weaker than angels, grigori, and the nephilim. They have equal strength to an experienced Guardian or a nosferatu. Vampires are significantly weaker than halflings.

Note: There are no demon halflings left; they have all been killed or are in the frozen field as punishment for breaking their bargain with Lucifer (only one halfling has been transformed back to human).

Vampires

A human who has lost much of his blood can be transformed into a vampire by ingesting either nosferatu blood or vampire blood. They are stronger and faster than humans. Except for their fangs, vampires look the same as when they were human. A vampire’s skin will gradually lighten without exposure to the sun; anyone with naturally dark skin will remain dark, however. He will not age. Hair continues to grow, but at an extremely slow rate. A vampire cannot shape-shift, will burst into flames in the sun, and falls asleep with the sunrise.

Nosferatu-born: A vampire who is transformed with nosferatu blood is more powerful than vampires transformed with vampire blood. His psychic senses are stronger, and while feeding, he can hear the person’s thoughts.

Feeding: A vampire must drink living blood every day. Although a vampire can survive on animal blood or stored blood for a short time, extended exposure to non-living blood suppresses bloodlust, brain function, and libido, and effectively shuts the vampire’s body down. A nosferatu-born vampire can exist on non-living blood longer than a normal vampire, but not by much longer.

Bloodlust: An overwhelming sexual thirst that vampires and nosferatu experience. A vampire is not always struck by bloodlust when he drinks; it is less likely to hit if he is not hungry.

The bloodlust rids the vampire of choice. If a vampire is suffering from bloodlust, once he has started drinking he is not able to stop until the bloodlust is satisfied. Drinking blood typically produces sexual arousal for both the vampire and the person he is drinking from (the exception to this is demons, who do not experience sexual arousal). If the victim desires a vampire suffering from bloodlust, the vampire will not be able to stop himself from having sex with the victim. If the victim resists, however, the vampire has a choice.

The bloodlust does not respect the free will of the vampire — only the free will of the victim.

Vampire blood: Vampire blood has healing properties. If it is applied topically or given intravenously, it speeds in healing damaged tissues and can offer the recipient strength. It cannot cure diseases, however.

Daysleep: With few exceptions (due to curses and/or rituals) all vampires succumb to the daysleep. Breathing and movement stops; only their hearts beat. If a vampire is teleported from one time zone to another, he will either fall into the daysleep (if he’s teleported to a location where the sun is up) or wake up (if he is teleported to a nighttime location.)

Communities: About two hundred years ago, vampires began forming communities to protect themselves from human discovery. Typically, the communities are ruled by one or two elders, who gain their position by killing the elders who came before them. Within the communities, either the elders or enforcers maintain order and destroy any vampires who do not follow the community’s rules. The most important rule: every vampire must have a partner with whom to share blood. Feeding from humans risks detection, so vampires each have one or two partners, and they feed from each other every day.

Consorts: A vampire’s blood-sharing partner. “Consort” is typically used by older or more traditional vampires, or vampires who aren’t in an equal relationship with their partner. Can be male or female.

Strength: Though physically stronger than humans, vampires are the weakest of all the supernatural creatures. A nosferatu-born vampire is about half as strong as a nosferatu. Because the vampires do not have to follow the Rules, however, at times they have more options and greater power to act than demons and Guardians do.

The Rules: Vampires do not have to follow the Rules as demons and Guardians do, but Guardians will hunt down and kill any vampire who breaks the Rules without a really, really good reason.

Humans

Are just like you and me, and most of us don’t know anything about demons, Guardians, or vampires. We aren’t as strong as those creatures, but we have one important thing they don’t: free will and the protection of the Rules.