Introduction to In Nomine
Overview of the Game
In Nomine is a game about angels and demons who struggle for control of Earth. Primarily, this means influencing the events to support their own vision of how reality should be. Player Characters can be angels, demons, humans aware of the War and potentially augmented by their awareness, as well as some others. Angels and Demons are quite high-powered compared to normal people. Not only are they stronger, faster, and of greater will, but they also have special powers as a result of their angelic or demonic nature. The "good" of angels versus the "evil" of demons is defined primarily by selflessness versus selfishness; demons are ultimately extremely selfish.
The tone of an In Nomine game can vary widely. When I run a game, I tend to make it a serious game— the War is serious, Heaven represents the side of the good guys, and souls are at stake. However, it's also a fairly cinematic game; this is about angels and demons after all, so it doesn't really make sense to get too bogged down into the details of fussy reality. That being said, the reality of character motivations and reactions still applies!
The Setting
The universe is divided into three planes: the Celestial Plane, the Ethereal Plane, and the Corporeal Plane. The Corporeal Plane is where much of the action takes place, and it is just modern day Earth (except that angels and demons are real, some forms of magic work, etc.). An angel or demon must have a vessel to exist on the Corporeal plane. This is, basically, a corporeal body that the celestial inhabits. An angel can take its (true) celestial form on the Corporeal plane, but it will usually be ejected from the Corporeal plane before long if it holds that form. What's more, this causes disturbance (see "The Symphony, God, and Lucifer" below).
The Celestial Plane is divided into Heaven and Hell. Whereas all of Hell is accessible, only the lowest level of Heaven is accessible to player characters. Human souls, after death, sometimes hang out on this lowest level. However, they may also ascend to higher heavens, which effectively takes them out of the campaign. Angels can go to Hell, but they have to be careful as many there would love to tear them apart. Demons, however, cannot go to heaven for long, as the divine radiance of the place tends to ablate them away. Most angels and demons spend most of their time on the Celestial plane. It is the favored servitors of the Superiors (see below) that get sent on missions to the Corporeal plane.
The Ethereal Plane, sometimes called "The Marches" is the land of dreams and myth. Humans (and animals) all have a "dreamscape" on the Ethereal plane, which they inhabit while dreaming. Additionnaly, creatures of myth, including the pagan gods, exist here on the Ethereal plane. (The pagan gods are decimated and weak as a result of the ascendance of monotheistic religions on Earth, as well as a crusade against them organized by Heaven several centuries ago.)
The Symphony, God, and Lucifer
The War started in the distant past when, after the Eden experiment, Lucifer and a third of the other angels rebelled against God. As a result of this, they Fell, becoming demons, and were cast into Hell.
Celestials— that is, those native to the Celestial plane, i.e. angels and demons— are able to perceive the interconnectedness of reality. The most common metaphor in use for this nature of reality is "The Symphony", and the perception is typically described as hearing. Angels perceive the true Symphony; demons, however, perceive a distorted version that is warped by their own selfish nature. Both, however, are able to perceive disturbances in the Symphony. A disturbance in the symphony happens when a celestial interferes on the Corporeal plane. The actions of humans, no matter the motivation, cause no disturbance. Whenever a celestial breaks something, harms someone, or uses a supernatural power, however, it disturbs the Symphony. Those nearby who can perceive the Symphony may hear this disturbance. Greater disturbances can be heard to a greater distance.
God does not show up in the game as a "person". Indeed, it might be argued that the Symphony is god, although Lucifer and numerous Ethereals would dispute this. Lucifer, however, is an individual, if a very powerful and scary one, and may well show up.
Exept for Lucifer— who will be seen rarely if at all— the most powerful beings in the game are the Superiors, the archangels and demon princes that all of the other angels and demons serve.
Angels
The two most important things about an angel are its choir (which is basically its race) and its Superior, the archangel whom the angel serves. All angels have both a resonance, as well as dissonance conditions. An angels resonance is a theme in the Symphony to which an angel is attuned; it represents something supernatural that the angel can do. Dissonance conditions are things that an angel should not do. If one violates one of its dissonance conditions, it means that it is acting against its very nature in such a way that the angel takes a form of karmic damage (just called "dissonance"). Too much dissonance in an angel can cause it to Fall. In addition, angels have attunements (powers granted to it by its superior), may know mundane skills, can perform songs (basically, magic spells), and may perform rites (to restore its store of Essence, which is what powers things like attunements and songs).
Choirs of Angels
Seraphim (the Most Holy): A Seraph has a resonance for truth. By focusing on somebody, it can tell if that person is lying or not. It is dissonant for a seraph to lie.
Chrubim (the Guardians): A Cherub is a protector. A cherub may attune itself to a person or an object. Therafter, the cherub, by concentrating, can learn something about the location and condition of that person or object. It is dissonant for a cherub to allow something to which it is attuned to come to harm.
Ofanim (the Wheels): Ofanites are manic; they're always in motion, and they love to move fast. Their resonance is for geography; they can pull out strands from the Symphony to figure out the fastest way somewhere, or where something is, even if they didn't previously know that. It is dissonant for an Ofanite to be trapped in one place.
Elohim (the Thrones): An elohite is extremely objective. This objective nature gives them a resonance for emotion; they can sense the emotional states of others. It is dissonant for an Elohite to act on its own subjective emotions, rather than on what is objectively best.
Malakim (the Virtues): There is nothing more honorable than a Malakite. A Malakite's resonance allows it to learn things about the honorable or dishonorable behavior of others. Every Malakite takes at least four vows; it is dissonant for Malakim to violate their vows. Unlike all other angels, Malakim do not fall. Malakim also have a reputation for being bad-ass.
Kyriotates (the Dominations): Kyriotates normally do not receive vessels as other angels do. Rather, instead of using vessels, they possess people and animals to serve as their hosts. This is their resonance. It is dissonant for a Kyrio to allow a host it is possessing to come to harm.
Mercurians (the Friends of Man): Mercurians understand humans better than other angels do. They love humans. Their resonance allows them to intuit relationships between people present. It is dissonant for a Mercurian to perform acts of violence against a human.
Archangels
The archangel that an angel serves provides the foundation for that angel's motivations. Each archangel is defined by a Word; some would say that the archangel is the Word, and as the importance of the Word waxes and wanes within the Symphony, so does the power of the archangel. Servitors of a given archangel will first work to promote the cause of Heaven, but as a very close second will work to promote their superior's Word in the Symphony.
Blandine, a Cherub, the Archangel of Dreams. Her perview includes not only the literal dreams of humans, but also the hopes and aspirations of huamns.
David, a Malakite, the Archangel of Stone. His domain includes both physical stone, as well as the bedrock of communities among people.
Dominic, a Serah, the Archangel of Judgement. He oversees the Divine Inquisition. His angels are tasked with judging other angels, making sure that they are staying true to heaven and true to their natures.
Eli, a Mercurian, the Archangel of Creation. Once one of the most important of archangels, in the last century he's gone AWOL, assigning many of his angels to be "in service to" other archangels.
Gabriel, an Ofanite, the Archangel of Fire. She is widely regarded as being insane, and is at odds with Dominic. Her word includes not only elemental fire, but also the fire of inspiration (Gabriel is herself a prophet), and the punishing fire that burns the cruel.
Janus, an Ofanite, the Archangel of the Wind. His angels never stay in one place for long, but blow through town, causing havoc. His domain includes not only the physical wind, but also the winds of change.
Jean, an Elohite, the Archangel of Lightning. Jean's word has become very important in recent decades as electronic technology has ascended in the word. Jean is the archangel that oversees technology, and that tries to prevent humans from acquiring technology and knowledge sooner than they should.
Jordi, a Kyriotate, the Archangel of Animals. Jordi does not like humans.
Laurence, a Malakite, the Archangel of the Sword. A former servitor of Michael, Laurence is relatively young as an archangel. However, he is currently the commander of heaven's armies.
Marc, a Mercurian, the Archangel of Trade. His word has also become stronger in recent centuries as commerce and capitalism has gained such a dominant role in human society.
Michael, a Seraph, the Archangel of War. God's original champion and the one-time commander of God's armies, Michael is now more the patron of the individual warrior, whereas Laurence is the commander of armies.
Novalis, a Cherub, the Archangel of Flowers. Her domain includes not only plants, but also peace, reconciliation, and forgivness. It's no accident that the "peace movement" of the late 1960's and 1970's was associated with "flower power".
Yves, the Archangel of Destiny. One of the oldest beings, Yves is thought by most to be closer to God than anybody else. (Michael might dispute this, and distrusts Yves.) It is the achieving of your destiny that allows you entrance to Heaven— whereas falling to your fate dooms you to Hell— so Yves' Word is of the utmost importance.
Demons
My games typically have the PCs on the side of the angels, so demons are usually adversaries. Whereas angels come in choirs, demons come in bands. Demons have their own resonances and dissonance conditions. However, whereas an angel may Fall if it gets too much dissonance, a demon just becomes more and more twisted. Demons also serve Superiors, and receive dissonance conditions as a result. However, the nature of the service is usually different from the nature of an angel's service. An angel wants to further its superior's Word and probably loves its superior; a demon, usually, will try to further its Superior's word, but ultimately probably hopes to assassinate and take over from its top boss.
Bands of Demons
Balseraphs are fallen seraphs; it's what results when a seraph is too fast and loose with the truth. They are liars, and can convince others to believe their lies.
Djinn are fallen cherubs; it's what results when a cherub becomes too obsessed with its charge. They also attune themselves to people and objects, but stalk them rather than protect them.
Calabites are fallen ofanites. The motion inherent in an ophanite becomes entropic random motion in a calabite, and as a result calabites are extremely destructive.
Habbalites are fallen elohim. They're deluded, and believe that they are the true angels, serving in hell. They're the ultimate manipulators, sensing people's emotions and using that knowledge to cause them harm.
Lilim are the creations of the demon princess Lilith, and do not represent fallen angels of any sort. (However, it is possible, if rare, for a Lilim to redeem, becoming a Bright Lilim.) They're wheelers and dealers, collecting and trading binding favors.
Shedim are fallen Kyirotates. Like Kyrios, they possess others, but instead of preserving them, they drive their hosts to ever greater acts of depravity.
Impudites are fallen Mercurians. They also like humans, but in a more condescending, cynical way. They like to use humans, leech off of them.
Demon Princes
Andrealphus, an Impudite, Prince of Lust.
Asmodeus, a Djinn, Prince of The Game. He is Dominic's opposite number, the leader of the secret police of Hell.
Baal, a Balseraph, Prince of The War. The leader of Hell's armies in the war.
Beleth, a Djinn, Princess of Nightmares. Beleth's opposite number. Indeed, before the Fall, Beleth and Blandine were lovers.
Belial, a Calabite, Prince of Fire. Not the sharpest knife in the drawer, but perhaps the most destructive knife in the drawer.
Haagenti, a Calabite, Prince of Gluttony. A relatively young Demon Prince who rose up to his rank starting as a lowly familiar. Cultivates an anti-intellectual air.
Kobal, an Impudite, Prince of Dark Humor.
Kronos, a Balseraph, Prince of Fate. An opposite to Yves, although Yves is an older and more primordial being.
Lilith is actually a human, albeit an immortal one. The original wife of Adam during the Eden Experiment, she walked away, putting her at odds with heaven. Lucifer later offered her the title of Demon Princess of Freedom. She is the only one who can maket he Lilim.
Malphas, a Shedite, Prince of Factions.
Nybbas, an Impudite, Prince of the Media. A very young Prince whose Word became ever more ascendant throughout the 20th century.
Saminga, a Shedite, Prince of Death. Another not-terribly-bright Demon Prince, he's the caricature of the cackling evil overlord if there ever was one.
Valefor, a Calibite, Prince of Theft. His servitors bear many striking similarities to those of Janus.
Vapula, a Habbalah, Prince of Technology. Whereas the archangel Jean is the curator of the secrets of the Unvierse, Vapula is basically a mad scientist.
Others
In addition to an angel, there are other sorts of characters you could play. Also, in addition to demons, there are other sorts of adversaries.
Soldiers are very special people. Some people have a potential to be something more. If discovered, they can be converted to the cause of Heaven or Hell, becoming either a Soldier of God or a Soldier of Hell. While not as powerful as angels and demons, they are very useful because they do not disturb the Symphony normally.
Mundane Humans make up the vast majority of the population of the Earth. Very few of them are aware of the War, and both sides generally want to keep it that way. However, there are some normal humans who are aware of what's going on, but who are not soldiers.
Sorcerors are humans who have learned the arcane arts. They often are dominated by, in the employ of, or working with ethereal spirits. However, demons seek to use these people, and angels seek to convert or destroy them.
Celestial Spirits are spirits that aren't quite enough to be angels or demons. On the heavenly side there are retrievers, and on the demonic side there are imps and gremlins. Some of these are servants or familiars to angels or demons on earth, others are generally out there serving the cause of their side in the War, but most are in either Heaven or Hell. Rarely, one of these may be fledged into a full angel or demon, almost always due to the direct action of a Superior.
Kittens are actually more important than everything else.
Books to Buy
The stuff above gives you enough of an introduction to figure out what sort of character you might want to play, and even to play in the game if you aren't terribly interested in game mechanics.
If you want to learn a whole lot more about the game world, what goes on and how things work, as well as about game mechanics, the In Nomine core rulebook is the book to get. The book is out of print, but you may be able to find one used somewhere. However, you can also purchase a PDF of the core In Nomine rulebook.
Some people argue that the introduction to the world is more coherent in GURPS In Nomine. While that may be true— the organization in the core In Nomine rulebook does seem at times haphazard— I have to admit I've always liked reading the color text and short stories in the In Nomine line.
If you want to learn more about playing an angel or a human, the Angelic Players Guide (out of print and not available as a PDF, as far as I can tell) is a good reference, as is the Corporeal Players Guide.
If you're playing in one of my campaigns, please do not read any of the "Revelations" cycle, as I will want to use stuff in there as source material (under the assumptions that the players don't know it). The titles in this cycle include Night Music, The Marches, Heaven and Hell, Fall of the Malakim, and The Last Trumpet.