Mage: The Ascension is a roleplaying game from White Wolf Game Studios. The World of Darkness is a fictional RPG multiverse. It is described as "gothic-punk" by the developers.
The game is generally contemporary, but can be played in all ages as the setting is quite flexible. The basic assumption of the game is that reality is malleable: What people believe exists is what actually exists. All player characters in a Mage game are mages, humans with what is called an "awakened will" or "Avatar". Mages have a coherent belief system (referred to as a paradigm) that provides an explanation for how the universe works. This explanation includes the ability to use magic. For instance, a shaman's belief that the universe is controlled by powerful spirits allows her to appeal to these spirits to miraculous effect.
The 9 realms of influence and control are as follows
Connection: The arts of Conjuration, Gates, Scrying, Warding, and Wayfaring. Connection deals with the connection of pieces of the whole with the whole, and each other. It allows for the manipulation of objects from afar, and bringing such objects together in space.
Entropy: Fate, Fortune, Decay, and Immutablity. The art of Entropy encompasses the slow slide towards the Void, that all objects endure. It can control how the slide happens, and guide an object or person along the path with good luck or bad. With great skill, it can even stay the ravages of the Void itself, and make an object or being immutable and unchanging.
Forces: Elemental forces, Weaponry, and Weather. The art of Forces is the art of power, and the way in which Force acts on other objects. Cold, heat, dark, light, motion and rest are all at the whim of a mage skilled in the arts of Force. A great storm could be summoned, or a hurricane could be made into a peaceful day.
Life: Transformation, Healing, Improvement, Creation. The art of Life is the art of change wiwithin living beings. Be they as simple as a plant, or as complex as a living being, minor changes or complete transformations are the realm of this Art.
Matter: Alchemy, Shaping, Conjuration, Forging, Transmuation. With the art of Matter, everything inanimate is at the whim of the mage. Metal can be bent with the mere thought, or lead turned to gold. At the higher levels, fully wrought items can be brought into existence from nothing.
Mind: Dreams, Empthy, Illusions, Astral Travel, Communication. The art of mind is the art of the mental. Anything that thinks, even with the most primitive emotions, can be influenced by this Art. And at greater skills, the Mage becomes aware of her own mind, and abilty to control it.
Prime: Channeling, Draining, Enchantment. Prime is the underlying fabric of the worlds. It is what makes reality "Real" instead of a fantasy. If everyday objects are a 'mold' in space, then prime is what fills those molds, and gives the empty 'mold' a shape that can be cast again and again. Without any of the other arts, it's useless, but with them, it can make all things. It also allows spells to be cast more easily. It is the study of mana, the fuel of magic.
Spirit: Shadow-walking, Spirit Speech, Possession, Fetishes, Necromancy. Spirit walking, bargaining with spirits, opening to the Second and Third Realms. Gateways and forging ephemeral tools. Contact, communication, and command of spirits of all types, from Ghosts, to Demons, to Angels. The threat "I'll rip out your soul and eat it!" is no idle one coming from a mage with command of the Art of Spirit. It is the BLACKEST of black arts, since doing so would fuels Blood Void directly.
Time: Perceptions, Temporal Control, and Prophecy. Control of the Art of Time allows the mage to see into the future, the past, and with great skill, to actually alter those streams of time, and fit new threads of reality into them. Time travel is hard, the realms dislike the paradox it generates, but it is possible.