The Three RealmsHell & Demons
Also known as The Second Kingdom and The Dark Kingdom. Hell is, as its name suggests, the home of the Demonic hordes. The forces of Hell on Earth are controlled by the powerful entity known as the Destroyer, who tasked his champion Straga to claim the Third Kingdom, Earth for the might of the demonic legions in their incessant struggle against the denizens of the First Kingdom; Heaven - the Angels. It is a place filled with fire and brimstone, where only the hard survives and power rules above all. Mountains of Fire and Volcanoes dominate the landscape, and the skies are eternally covered in blood and darkness. It is said that no one aside from Demon folk has been able to actually survive within the kingdom for more than a single day. The Kingdom is dominated by a single race: Demons. Bred in pits of fire, the almighty demon folk have tamed the fires of the land and relish in its power, using the very terrain to mold their bodies into war machines. Demons are Hell's residents and rulers of the Second Kingdom. Demons tend to be characterized by bloodlust, cruelty, utter selfishness and brutality. In fact, most demons use no weapons in battle save for their own claws, talons, and fangs. Though they have some projectile weapons, demons generally have a very low technology level, preferring raw strength and skill. Unlike the Angels, demons have few qualms regarding whatever methods they use to achieve their ends. For example, the Angels abhor necromancy, but it is common amongst the armies of Hell, as seen on Earth.Society
Demon society appears to be a sort of feudalism based on a viciously violent meritocracy, where one's position is determined by the level of power they possess. There are many powerful demons that carve out their own domain by virtue of their own prowess, but all are sworn to a single ruler of great power, currently the Dark One. The ruler's position is not set in stone, however, as a sufficiently powerful demon may overthrow him and assume the role. Samael, for example, was believed to be next in line for Hell's throne prior to the Apocalypse.
Hell's hierachy is too chaotic to have set ranks and positions.
Heaven & Angels
Heaven (also known as The First Kingdom and the White City), is one of the realms featured in the Darksiders Series. The domain as well as an outpost of the Angelic host, its residence are wholeheartedly dedicated to what they believe to be the Creator's will, though he does not interfere in their affairs. While many Angels still remain in the Kingdom itself, many of them have died in the Apocalypse. It is unknown if there are more Archangels within, although it is very possible. Angels are a strong warrior race from Heaven, with only slightly more liking for Humans than Demons. Angels float aloft on luminous wings, and while they often aren't quite as resilient as some of the more powerful demons, they carry far superior weaponry, including heavenly swords, halberds which can fire blasts of energy, Salvation and Redemption cannons. Angels can ride Angelic Beasts into battle, for times when just a little more firepower is needed. Angels have not only powerful weaponry, but also potent armor which they can be seen wearing at all times.Society
Angel society is typified by a militant obsession with the righteousness of their cause and a fervent belief in the rule of law, order, and justice. The Codex Bellum provides an immensely complex code of laws that rule every aspect of Angel society, even strict regulations regarding what romantic relationships would be condoned and which would be condemned, though it was not unknown for angels to bend or break these laws. There appear to be two distinct sections to the angelic military. Most well known is the Hellguard, the army dedicated to the destruction of demonkind, but there have also been references to a White Army, which is likely the section dedicated to the defence of the angelic realms. The angelic system of government has never been defined, but there are at least two positions of great power.
Archangel - This appears to amongst the highest if not the highest position in the angelic hierarchy and legions. Whether it is a rank or an actual type of angel is ambiguous. Both Abaddon and Azrael are Archangels.
Archon - The exact nature of this position is ambiguous. It appears to hold great authority. Some have speculated that the Archons are battle-priests and relic keepers of the angels, as both Archons so far mentioned have been wielding or safeguarding items of great significance to the Angels: the Angel Key and the Rod of Arafel.
Earth & Humans
Earth, also known as the Third Kingdom or the Kingdom of Man was one of the Three Kingdoms and home to the Human race. It is the only known realm to explicitly lack an incarnation of the Tree, as its manifestation was burned to cinders by the Charred Council to restrict access to the realm. A realm void of any green or nature, the humans have terraformed the earth into an industrial megaplanet that produces weapons and technology on par with the realm of Heaven. Thousand of years passed since the first, premature Apocalypse caused by War in their modern age, and since then they have advanced to a level that the Charred Council deemed powerful enough to finally hold its own in a battle with its neighboring realms. Their technology has eradicated disease of any kind, increased the human lifespan to an upwards of three hundred years while maintaining youth, and have explored every inch of their planet. While they are not as strong as Demons, or as agile and superior as Angels, they are by far the most cunning of all three races. Their intellect has advanced with the evolution of the species, allowing for a larger brain and a more efficiant memory, as well as increased bodily functions such as improved eyesight and sensitive hearing. The clear underdog in this war, the humans rely on their wits and battle strategies to ambush and defeat the armies of Heaven and Hell, in Gorilla Warfare like tactics to secure victory. Society
Originally humans were given the realm of Eden as their home. However, Absalom believed that the Nephilim deserved Eden since they had no realm of their own and sought to conquer it. The resulting clash between the armies of Heaven with the Four Horsemen at their side and the Nephilim resulted in the destruction of Eden and the annihilation of the Nephilim. Humanity was then relocated to the Earth, where the Charred Council ordered that the Tree on that world destroyed to prevent unsanctioned entrance to the realm by the other kingdoms. Since then, Mankind has gone through several stages of rule until this day. Gone are nations and tyrants, gone are wars and borders. The Kingdom of Earth now united under a single banner and a single Monarchy. Every Monarch is no longer selected through politics, but in trials of controlled combat free of corruption and influence. Humans have evolved past simple political thinking, and have become aware of the threat of the other realms. Ever since, power was preferred over politics. As such, the King of the Realm is, as should be, the strongest. Weapons such as nuclear weapons remain, however many Humans have become fond of their past's weapons such as swords and shields. Such things have been upgraded with current time's technologies, making them far more effective.