Phantom

Phantom (ファントム) is a broad term for ghosts, yōkai, monsters and other supernatural beings in the Musaigen no Phantom World series.

Definition
Most phantoms existing are said to be harmless. But there are also phantoms that may lead people afield. There is still a lot of things about Phantoms that are shrouded in mystery. But they are a figment of the imagination, and/or an apparition or specter. They are thought to be hallucinations or the man-made manifestations of such, and it's believed that Phantoms owe their existence largely to the human subconscious and language centers. Ever since the Phantoms appeared, humans with special abilities have been born. There are many Phantoms in all shapes and sizes. Some examples are:
 * Ruru - She is a friendly phantom and has the appearance of a human, albeit an extremely small one.
 * Enigma - An evil Phantom that takes the appearance of a human. She can possess humans and steal the special abilities of ability users.
 * Ayumi Kitajima - A Phantom who disguised herself to be a human. A manifestation of the frustration the drama club felt from losing to other drama clubs for 10 straight years.
 * There are also many other Phantoms, for example, sunflower lookalikes, Tsukumogami etc.

History
A decade ago, the Alayashiki Research Facility was hit by a terrorist bomb, resulting to a certain virus that infects the brain to spread out. The large-scale bio-hazard almost affect the majority of the population, causing some changes in the brain function. This leads to the people becoming aware of the Phantom's existence. Phantoms are once considered as fictional or perceptible to only animals and humans with ESP. But after the tragic event in the facility, they are defined as the creatures that broke down the wall between reality and myths. Addition to the mentioned information, breastfeeding infants manifested superpowers giving birth to abilities, an example of which are the protagonists of the series.

Attributes
All Phantoms possess one of 5 attributes/elements, who are similar to the 5 elements of Chinese theology. Currently, Mai Kawakami is the only individual in the series that can control the five attributes and use them to seal malevolent Phantoms.