Since I can't read Japanese, and all I can find are toy-related articles, it seems there's really only so much one can say about the notorious Shunya Yamashita.
Like some of my favorite Heavy Metal artists, all he seems to draw is sexy nymphs.
Sure, he'll draw the occasional big, badass dude, or as you can see above, the nymph with a big gun/hairdryer thing, but that's all part of Mr. Yamashita's appeal.
Wikipedia article? Would you care if I said he worked as a character designer for various Japanese videogames, eventually landing (quite comfortably) on toy design?
decent write-up for Mr. Yamashita's 2008 artbook "Wildflower".
Finally, you might come across this conservative looking illustration below, with a heading called "rick-o-sound". I'm not sure why Japanese likes naming things like this, but it seems its his personal toyline.