This is a list of the characters featured in Touhou Project, a series of shoot 'em up and fighting video games by ZUN from Team Shanghai Alice.

Most Touhou characters reside in a fictional realm called Gensokyo (幻想郷, 'Land of Illusions'), where humans and yōkai coexist.

Gensokyo's culture is like that of feudal Japan, but the Touhou games take place in the present day.

Reimu first appeared in the original game, Highly Responsive to Prayers, and Marisa in the second, Story of Eastern Wonderland.

Since she likes yōkai extermination itself, when incidents do not occur for a long time, she grows irritated due to boredom.

The job of the miko of the Hakurei Shrine is to exterminate yōkai and resolve incidents, and Reimu herself possesses considerable power, but since she habitually lives a life of drinking tea and taking naps, she does not have enough training.

The hakama is unconventional in its appearance due to the fact that the sleeves are detached, exposing her armpits, which has become the subject of an Internet meme.

In 2006, dōjin music group IOSYS, who make Touhou-themed music parodies, released the song Tsukiyo wo Kakusanai Teido no Nouryoku?,[14] which made frequent usage of the line "Waki miko Reimu" (armpit miko Reimu), leading to an unofficial nickname.

While she is prone to violence, selfishness, and other disagreeable behaviors, she is an honest and hard worker, usually on the front lines of defending Gensokyo whenever an incident occurs.

Her name is a reference to Letitia "Letty" Blacklock, a character from A Murder is Announced, by Agatha Christie.