This is a headcanon of the Touhou Project, and a typical fan-made trashpost. The series is forgiving for those who didn't know (or know little) about Touhou since this is mainly a joke anyway lol. Any material relevant to Touhou is mostly based on fanon.
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Sypnosys: A degenerate journalist found himself in the dream of a nonexistent vampire, like his dad, which he was eager to find. But a mysterious woman named "Yukari" forced him to stay in the vampire's dream for unknown reasons. His wish to return home in Ohio with his dad helped him survive in Gensokyo, a world of monsters "youkais" and lack of common sense. However, it would not be so easy as his soul happened to be mixed with other ghosts from Ohio, forcing him to have a goofy ahh life with strangers in the same body.
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Note: The details in the novel's glossary are directly from Touhouwiki.