Mushi (虫) are mysterious parasites that appeared ten years prior to the start of the story. They feed off the dreams of its human host and provides supernatural powers in exchange. Mushi mainly focus on young generations, who are full of emotions, dreams and hopes. The Mushi are a target of fear and discrimination, as their supernatural powers are classified unhuman. Although there had been sightings in many areas, the government continued to deny the existence of Mushi for years.[1]
Furthermore, the Mushi may be categorized into three different types in accordance with their traits — Minion type, Special type, and Fusion type. In addition, those that contain purely offensive combat power, and are equally capable Hosts will be classified as "Kashu"; those that have a unique special ability will be classified as "Ishu"; while those that have a special condition with a great importance or shrouded in mystery will be known as "Hishu". These types are then be further broken down into different levels of threat, ranging from level one to ten, one being the highest. Currently almost all of the Hosts are classified as Kashu. However, only a very few Mushitsuki are worthy enough to be ranked into levels within this majority.[2]
Mushitsuki (虫憑き) are the "hosts" who are possessed by the Mushi. They are broadly separated into three types: One is the Minion type where the Mushi exist with a physical body and obeys the host. Another is the Fusion type in which the Mushi assimilates with the host's body, giving them supernatural physical abilities (Anabolic). Lastly is the Special type which does not have a physical body, instead giving its host the ability to manipulate various power at will. In exchange for using these powers, the host's own dream would be consumed by the Mushi.[3]
Hosts whose Mushi has been killed become Fallen (欠落者 Ketsurakusha). They lose their dreams, memories, emotions and because they have no desire, they will starve to death or lose their lives due to other causes, as long as they are not given any commands. So far Shiika is the only fallen who regained her memories and emotions.
Maturation
When the Mushi has managed to consume enough of the host's dream to reach a level that it could evolve itself, the Mushi will first of all rebel against its master. It will then leave the host and become a matured Mushi. Afterwards, the host who was drained until they had nothing left of them will die.[2]
The "Original Three"
Elviorene (エルビオレーネ Erubiorēne): Oogui (lit. "Gluttony")[1], creator of Minion type. A tall figured woman wearing a crimson red coat.[4]
Three mysterious beings that are the source of all Mushi phenomena. They consume dreams when they create Mushi and grant them to a host. Each of them creates a different type of Mushi, and has different preferences on dreams to consume. Neutralizing these individuals is supposed to be the top objective of the Special Environmental Preservation Bureau, though SEPB may have a different priority than what they claim to hold.
List of Mushi
Kakkō
Kakkō (かっこう, lit. "Cleridae") is the Mushi of Daisuke Kusuriya. It is classified as a Fusion type.[1] It can synchronize with Daisuke's gun and his body, increase the range and power of the gun and grant him super human strength, speed and durability. It is hinted that the more powerful he makes the bullet, the more his dreams or energy is drained.
Fuyuhotaru
Fuyuhotaru (ふゆほたる, lit. "Winter Firefly") is the Mushi of Shiika Anmoto. It is classified as a Special type Hishu.[1] While the crystal clear insect's outer appearance is that of a firefly, its eight legs are pure-white, and it features four compound, red eyes on top of its head.[5]
Its power is Substance Metamorph (Anything that is touched by the snowflakes produced by it will not able to keep its original shape. Within the range of snowflakes falling, Fuyuhotaru has the power of overwhelming and complete destruction; the Mushi shines like a bright ball and is able to cause heavy impacts with high velocity tackles. Furthermore, it can create a snow storm that kills other Mushi in it, presumably by high atmospheric pressure. This Mushi is considered one of the most dangerous out of all and was therefore terminated years prior to the start of the story.
Nanahoshi
Nanahoshi (lit. "Seven Stars") is a seven-spotted ladybug Mushi and belongs to Rina Tachibana. Rina is able to ride Nanahoshi to fly. Her most powerful attack used on a berserk Centi seems to be a highspeed sonic slash.
Centipede
Centipede is a centipede Mushi. It has a thin and long body with countless feet, spikes on top of its thick shell and six eyes. The sharp claws of the centipede, which look like dancing whips, extend out several meters.[2]
Morpho Butterfly / Morpho Patroclus
A brightly silver colored Morpho butterfly of a Fusion/Special type, with brilliant scales and wings that give off a silver light, beautiful pollen on its wings, and four antennas. It possessed Mari Hanashiro until she was consumed by it, the latter turning her dream over to her best friend and new host Arisu Ichinose. It has the ability to turn items into a long silver lance. The antennas of the Morpho butterfly climb up to the handle like ivy, and give off an imposing presence akin to that of a polished sculpture; four big wings spread out, and one of them the pointed blade that glows. The pollen from its wings have destructive power on impact.[6]
