Shunmu (a Touhou LW original) refers to mist during spring. The natural laws of Phases do not apply to her temperament as she is a native of Makai. Beings from Makai are called Makaijin, but this is thought to merely be a name used to identify beings native to that world. However, beings with a personality transformed into magical creatures by the magical power of Makai, are apparently called majin. It seems that this Koakuma is not a majin, even though she is from Makai. She has been a magical creature since her birth in Makai and is probably a native devil. She is a part of Makai and was created by the god of Makai. She is weak to the sun (Sun Essence) due to the characteristics of the Scarlet Devil Mansion. Since a sun also exists in Makai, this weakness does not seem to be based on her true nature. On the other hand, she is strong against precious metals (Metal Phase) because Patchouli used an alchemical technique with her elemental magic to summon her. This resistance is also a kind of limitation placed upon her from the summoning, and it seems her true nature has different weaknesses and resistances.

The ability of Koakuma with the twisted fate (a Touhou LW original). Unlike her original ability, this one has become multiplexed and localized from countless compounding distortions. ...Thanks to newly discovered true data, it is now known that Koakuma's ability lets her instantly find books. Despite its simplicity, it is an incredibly useful ability that lets her sift through vast sums of data. Without it, she would need to sort the books on the shelves and keep a constantly updated catalog just to know where to start searching for a specific book―a task made especially difficult in the Great Library because it continues to expand in accordance with Patchouli's needs. The Koakuma of our world's origin is unknown, but this world's Koakuma seems to be from Makai. There are many mysteries surrounding Makai. It is thought to be another world, but there are various theories as to what kind of world Makai is. In general, the world humans live in is bound by physical rules. It is, so to speak, a physical world. In the past, the existence of various non-physical phenomena has been proposed, but they were eventually explained as physical phenomena. In the human world, everyone has resigned themselves to the belief that even phenomena which currently have no scientific explanation will be explained someday. Makai, however, exists in stark contrast to the real world. It is a world built on magical principles that tend to exclude scientific explanations. In Makai, there is hardly anyone who believes in science... Presumably. That said, it would be premature to conclude that magic and science are mutually exclusive. Some studies seem to view these two principles as balanced on the opposite ends of the same scale or as two sides of the same sheet of paper. Others believe there is a single truth that has multiple transformative interpretations, such as magic and science. If this is the case, that would mean there is little difference between the physical world and Makai. They would be like two different countries or planets... The Makai where this Koakuma originally lived was apparently situated next to the human world, separated by a single door. The beings there are like migrant workers who make a living in the human world when called there. Humans called this summoning magic. Summoning magic is a means of traveling between worlds. Thus, there are many complex restrictions regardless of how easy this magic may be to perform because it is a serious matter to cross or temporarily break a boundary. Also, countless types of summoning magic exist because of all these restrictions. The devils' service industry is incredibly diverse. It is, of course, most profitable to summon a whole devil, but the price that summoners are capable of paying has dwindled over time. In the past, summoners could perform on-the-spot magic to gain permission to copy skills, abilities, and sometimes bullet patterns. They could also easily summon just the spiritual body of a devil, lend a part of their physical body to the devil, or divert resources from Makai. The magical services that used summoning principles boasted endless possibilities. However, the scale of these services continued to decline. This has led to a gloomy atmosphere in the Makai human service industry. They believe the practice of summoning will probably die out once they have earned all the magical energy in the human world. In the midst of this dire situation, a devil received an offer to be summoned! But there were three conditions―she must organize the books, manage the summoner's original Makai environment in the human world, as well as one other condition... She thought such a large order would only be possible from someone as powerful as a vampire's attendant magician (which the summoner ended up becoming). The summoner's unfinished Philosopher's Stone was far from sufficient as payment. But Koakuma accepted the offer anyway because she was interested in the summoner. The summoner was a magician who devoted herself to researching the crystallization of knowledge without regard for the physical or spiritual cost to her own being. She was just like the mages of old... But even that was only an excuse. Magic and Makai businesses follow the absolute law of equivalent exchange. Unbeknownst to the summoner, the Koakuma of this world left a few things behind in Makai to compensate for the insufficient payment. She left most of her power, some of her physique, some of her memory, and her name. Leaving these behind was just enough to level the scales. But Koakuma was satisfied and had no regrets until the very end. How could she refuse with such great conditions? She was tasked with organizing the books, managing the summoner's original Makai environment in the human world, and being the summoner's partner in conversation.