Touhou is set in Gensokyo, a fictional land that its culture vaguely resembles that of feudal Japan, with a lot of folktale elements added on. On Gensokyo lives Yukari Yakumo, one of the strongest youkai, as her power to manipulate borders is close to the power of a god (Her next to last atack on the video game is called "Boundary of Life and Death" and she isnt buffing about that) but she rarely uses her powers and she is extremely lazy. Some time on the past Yukari gathered Gendokyo strongest youkais and using her power she went to the moon (wich is poblated by the lunarians, an extremely advanced society that combined technology with magic) with the idea of conquering it and gaining knowloge of the moon technology, there is little info of what happened but the fact that yukari's army lost against the moon technology is for sure.
Touhou Bougetsushou ~ Silent Sinner in Blue covers yukari second attempt to conquer the moon. The manga itself its really good and the characters really resemble the original ones, the story gets really exciting and you always want to keep reading.
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However the problem is that even thoughis prensented as a serious work, in the end it twist into the same ending of all touhou games "... and then thay ahd a tea party" making it an anticlimatic ending for one of the best storys and characters out there.
