Chemtrail (a Touhou LW original) refers to a conspiracy theory about condensation trails from aircraft. This is an apt temperament for Sumireko Usami, who is an occult maniac with supernatural powers. Sumireko is endowed with Fire Phase, with her burning passion, and Star Essence, because of her curiosity and free spirit. The formless and passionate Fire Phase resists Wood Phase, because wood feeds fire, but it is weak to Water Phase, because water dampens fire. The diverse and uncooperative Star Essence resists the cooperative and indecisive Moon Essence, but it is weak to the charming and arrogant Sun Essence.

This is the ability of Sumireko Usami, a girl with real psychic powers who calls herself the first president of the Secret Sealing Club. People who claim to have extrasensory perception or supernatural powers in the outside world are mostly frauds, but Sumireko is genuinely a human who can use psychic powers. In fiction, heroes and villains with psychic powers are generally depicted as having a single type of power. But Sumireko, who has psychic powers and actually exists, has displayed various psychic powers, including manipulating objects with her mind through telekinesis and psychokinesis, traveling from one spot to another instantaneously with teleportation, manipulating energy with pyrokinesis and hydrokinesis, levitation, and flight. She is probably capable of using other psychic powers, and maybe even all of them. This might suggest that there is some sort of universal source for all the psychic powers that truly exist... Or perhaps people who can use psychic powers are like smartphones in how their functionality can expand and diversify in a myriad of ways as long as they can install the relevant app. It is incredibly difficult to differentiate psychic powers from magic or the abilities that youkai use. However, psychic powers seem somewhat appropriate for the youth, who are unique in the way that they believe they can do anything, and for children who have the potential to become anything. This ability could become incredibly potent if Sumireko trained it... but most high-school students would rather spend their youth having fun and enjoying themselves rather than train, and Sumireko is no exception. Sumireko previously tried to invade Gensokyo after discovering it on her own, but now she has a "dreaming disease," which makes her visit Gensokyo only in her sleep. This was not triggered by her ability but by the unique relationship between Sumireko and Gensokyo. While the exact details are a mystery, this relationship may have something to do with the nature of the barrier that surrounds Gensokyo or Sumireko's state of mind. It is not known how long Sumireko will continue to be able to visit Gensokyo. However, as long as she remains a child, she will probably keep her psychic powers and her connection with Gensokyo.