Kouchuu (a Touhou LW original) refers to a light pillar, a vertical beam of bright light that appears to extend from a distant light source. This is an apt temperament for this Mokou, who can create flames at will. She's imbued with Fire Phase since she can manipulate fire, and Sun Essence, since she has grown so accustomed to her routines that she now follows them without question. 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 alluring and arrogant Sun Essence resists the diverse and uncooperative Star Essence, but it is weak to the cooperative and indecisive Moon Essence.

The ability of Fujiwara no Mokou from the world of eternal night (a Touhou LW original). It is essentially the same as our version of Mokou's ability. However, this Mokou may be involved in prolonging the Eternal Night Incident. Death gives meaning to life, and dying provides proof someone was alive. Death borders life, and life borders death, so you could say the immortal people of Hourai continue to live and die without end. But you could also say they're neither alive nor dead, having been robbed of such concepts. Fujiwara no Mokou is an immortal human who has now lived for over a thousand years. With her being both immortal and a human, what goes on in her mind is beyond imagining. Originally, Mokou lived as a young girl, but that all changed when her father got involved in a certain disturbance. The one behind said disturbance was none other than Kaguya Houraisan. Since then, Mokou's thoughts and actions have all centered on Kaguya. Her hatred for the Lunarian fueled her on, and when Kaguya returned to the Moon, Mokou sought to ruin the gift she had left behind. She succeeded, but fate had a cruel twist in store for her... Mokou became an immortal person of Hourai. She hid from the world, keeping her immortality secret, and sat while countless years trickled by. The people she knew passed away one by one, and she lost all hope of ever connecting with anyone again. While she may not have died, she surely experienced great hunger and sickness over the years, not to mention the loneliness and despair that all humans know. She grew weary of it all... her grief, her cruelty, her callousness, even the self-hatred that accompanies such feelings. A person of Hourai lives too long to keep the flame of human emotions alive. No thought or feeling a person has can last forever. Friendship, love, and even rivalries are all washed away by the torrents of time. Mokou poured her efforts into helping people but grew tired of it. She focused entirely on exterminating youkai but, again, grew tired of it. Eventually, she thought her consciousness would be reduced to a flame flickering endlessly in the void between life and death... But then, in what can only be described as a stroke of good fortune, she stumbled across Kaguya Houraisan's shadow in a place far from human civilization. Mokou felt the fires of hatred in her heart reignite. "At last," she thought, "I'll be set free from my hunger..." By the time Mokou found Kaguya, it's believed she'd already broken through several "barriers." If you assume Eientei and the bamboo forest had appeared in Gensokyo by that point, Mokou must have too. This may have something to do with the fact Fujiwara no Mokou, the human girl, no longer existed and had, in essence, died. It's also possible that by then, Mokou had broken through Tewi Inaba's human-repelling barrier around the bamboo forest as well as the seal Kaguya had placed on Eientei to isolate it from history. (It's likely the seal in question was skillfully designed to allow Kaguya to enter and leave Eientei at will.) Mokou finding Kaguya was either an extremely unlikely occurrence spurred on by fate or engineered by someone pulling strings behind the scenes. While we're on the subject, wasn't there an acquaintance of Mokou's who manipulates history...?