At least some content in this article is derived from information featured in: Fantastic Beasts: The Secrets of Dumbledore & Harry Potter: Magic Awakened.
An Obscurus was the manifestation of the repressed energy of a young wizard or witch (known as an Obscurial). Described as a "dark" and "parasitic" force, an Obscurus was created when the wizard child in question consciously attempted to repress their magical abilities or were forced to do so through physical or psychological abuse. This energy could manifest itself as a separate entity that could erupt in violent, destructive fury.
When an Obscurial lost control, the Obscurus force was released, often focused on the cause of the Obscurial's torment, but also causing destruction in its wake.
The Obscurus could be largely invisible or appear as a flying, incorporeal, and amorphous entity with the appearance of a black, fluid-like cloud, or a violent torrent of darkness, sometimes with a reddish core. Some described it as a "dark wind" or "dark mass" with "shining white eyes". Its appearance could be oleaginous, or "rich in, covered with, or producing oil; oily or greasy". There had also been instances when a face briefly emerged from the shadowy entity, or a white glowing image of the host appeared inside of it.
The size and might of an Obscurus depended on the innate power of its host; the more powerful an Obscurial, the more powerful their Obscurus. When an Obscurial reached their emotional and mental breaking point, they could lose control completely and physically transform into an Obscurus. Its size and mass at specific times may also have been connected to the level of negative emotions that triggered it at that instance, as well as the current mental state of its host.
In this state, they were enormously destructive to their surroundings, to the point of causing objects to levitate or break without physically being in contact with them. This notably caused damage to structures and objects near the host. However, they could be calmed down by someone they trust, which causes them to revert to their corporeal state, though being emotionally conflicted could cause the Obscurial to transform back and forth.
An Obscurus often targeted people that were the source of their host's distress, as Credence Barebone's Obscurus went after Henry Shaw after he was insulted by him, though it took longer to attack Mary Lou Barebone since Credence was so emotionally close to her. When his adoptive sister ran in fear of him and Gellert Grindelwald, in the guise of Percival Graves, stated that he had lied to Credence about taking him in as a wizard, Credence lost control completely of his Obscurus, causing wide-spread damage in New York in December 1926.
An effective defence against Obscurus and death from his hands was a very strong Shield Charm. Gunnar Grimmson did that in Paris in September 1927 when he killed Irma Dugard, which enraged Barebone to the extent that he wanted to kill him.
When an Obscurus killed someone, it left specific marks on the victim's body, largely focused on their face.
It seemed that Obscurials could not be killed in Obscurus form; the Obscurus may have be shattered but the Obscurial themselves would survive, as Credence Barebone did in December 1926 after being assaulted heavily by offensive spells cast by MACUSA Aurors, in their attempt to destroy him. However, Credence was noted to be an unusually powerful Obscurus, which may well possibly have contributed to his remarkable survival.
- Harry Potter and the Deathly Hallows (First mentioned)
- Fantastic Beasts and Where to Find Them: The Original Screenplay (First appearance) (First identified as Obscurus)
- Fantastic Beasts and Where to Find Them (film)
- The Case of Beasts: Explore the Film Wizardry of Fantastic Beasts and Where to Find Them
- Fantastic Beasts and Where to Find Them: The Art of The Film
- Inside the Magic: The Making of Fantastic Beasts and Where to Find Them
- Fantastic Beasts: The Crimes of Grindelwald - The Original Screenplay
- Fantastic Beasts: The Crimes of Grindelwald
- Fantastic Beasts: The Secrets of Dumbledore - The Complete Screenplay
- Fantastic Beasts: The Secrets of Dumbledore
- Wizarding World
- LEGO Dimensions
- Harry Potter: Wizards Unite (Mentioned only)
- Harry Potter: Magic Awakened