Astral Line: A river of spiritual energy, invisible for the human eye, that is the source of life of every living being in the universe. The Astral Line is also the energy source of the powers of a demon. 

Contract: A pact between a hornless demon and a human. Hornless demons are unable to absorb the energy of the Astral Line, the source of their powers. Since the Astral Line is also the source of life of human beings, a demon can take energy from the lifetime of a person desiring to use his powers and pays his debt with services.

Eden: The Sinner’s headquarters, a large floating fortress hidden in the clouds.

Exorcist: A member of the Magdalan Order able to fight against demons and monsters.

Geas: A barrier that turns all demons with horns into Legions, that is, deformed monsters.

Holy maiden: A prophet. A person able to use the power of the Astral Line to see the past or the future.

Horns: Astral-absorbtion organs that demons use to absorb the energy of the Astral Line, the source of their life and their powers. If they’re broken, the demon is condemned to a very slow death, unless he or she finds an alternate way of getting the energy they need.

Jewel witch (or Jewel summoner): A person able to use the power of magical jewels.

Legion: Low ranking demons. They have different shapes and sizes, usually deformed and monstrous, and have very little intelligence.

Magdalan Order: A religious, militaristic organization that specializes in battling all sorts of monsters and investigating mysterious supernatural cases. There are several branches in the United States, but some of the most influential ones are in NY and Chicago. The Order also has the duty of protecting people blessed with special abilities (like the Apostles) from any evil person who desires to use their powers for their own ambitious purposes. The Magdalan Order is also a powerful, technologically advanced organization, and its members have to undergo a very difficult military training and are sent to all kinds of dangerous missions.

Minister (or priest): A male member of the Magdalan Order. Ministers are able to use all sorts of weapons, but they seem to be experts in hand-to-hand combat.

Nun: A female member of the Magdalan Order. Nuns are able to use different kinds of weapons (mostly firearms) and other types of equipment (like cross- barriers).

Oratorio: A large room in Aion’s fortress where the 7 Apostles gather to collect Astral energy. 

Pandaemonium: 1) The demon queen, mother of all demons. 2) The demon society, that is hidden deep under the sea and is named after the queen.

Pursuer: A demon (usually a powerful, high-ranking one) that is in charge of hunting down the Sinners. All demons from Pandemonium are potential pursuers.

Sinner: A demon that betrayed Pandemonium, the demon society. There are only 6 of them: Aion, Chrno, Jenai, Rizel, Sheda and Wid.

Soul: The lifetime of a person. Not to be mistaken with a person’s “spirit”.

Time Freeze: A time barrier that can turn people and/or things completely or partially into stone. Its effects are reversible. This ability seems to be almost exclusive of Chrno, though Joshua is also able to use it due to the power of Chrno’s horns.