Shadow Magic:Users are able use a form of magic that is related and based on darkness and shadows. For example, one can us this magic to gain access to (esoteric/mystic/magical) shadow-related abilities (E.g. Shadow Manipulation) or to cast spells that require or are related to bones (E.g. an Astral Projection spell or Healing spell).
Darkness Manipulation:Users can create, shape and manipulate darkness and shadows. By itself, darkness is mostly used to cloud everything into total darkness, but by accessing a dimension of dark energy it can be channeled to a variety of effects, both as an absence of light and a solid substance: one can also control and manipulate the beings that exist there, create and dispel shields and areas of total darkness, create constructs and weapons, teleport one's self through massive distances via shadows, etc.
Dark Arts:The user can utilize the Dark Arts, dangerous system of techniques based around a darker side of magic that typically used for selfish, self-serving and/or nefarious purposes. Though it is not necessarily "evil" magic, dark arts tend to focus on destruction, harming, cursing and otherwise complicating the lives of other people while advancing the user's state.
Dark Form:Users can transform into a state of being, primarily due to the influence of dark or negative forces, in which their darkest intentions, emotion, and powers are fully-fledged. In this form, the user's abilities are greatly enhanced, some able to manipulate powerful dark forces. However, the user is highly aggressive and quick to anger, making them a threat to anyone around them and themselves.
Esoteric Darkness Manipulation:The user can manipulate the esoteric side of the darkness/shadow, with special properties and a mystical nature to it. With mastery, the wielder could use the esoteric element for a variety of magical effects.
Shadow Stealth:The user can hide within the shadows and remain undetected. They can use this technique to spy on individuals without leaving behind physical evidence.
Spell Casting:The user can cast spells, which are formulae for producing specific magic effects. Such formulae are often a series of magic words and incantations, but they can also take the form of specific thoughts, gestures, rituals, etc. If the user is powerful or skilled enough they can cast their spells as nonverbal spells which doesn't require them to say the incantations to preform the spell.