@Ardainian Right I mean, there ARE a lot of Touhou games as well, hell, the Switch has a bunch of them now, but I'd assume that the bulk of their "mainstream" Western popularity is driven by art, music and memes. 

 @Christi Junior @Ardainian Right 
And, especially, hentai 

 @b8ed4588 @Ardainian Right Already covered that:

https://www.youtube.com/watch?v=0_6lFkOg7ko