It's hard for me, personally, to speak to his image in Japan, but I'll address a little of what I found when I spent some time in China last year. While he wasn't super mainstream popular over there, I discovered that, at least in the neighborhood I was staying in, which was located near a university, there were a lot of young, hip, trendy, cutting-edge uni students who were all over him. It wasn't the nerdy students; it was a more fashion-forward crowd (though I have no idea if this only applied to the place where I was staying, so take my info with a bit of perspective). I also picked up a bunch of Chinese music magazines that focused on foreign music and he was always mentioned, whether it was for his fashion style, his looks, or his music. He seemed to be a sort of cult figure there, at least amongst the people I spoke to.

Then I met a Japanese girl there, who had never even heard of him or L'Arc~en~Ciel before but was instead all over Gackt and m-flo. I was so disappointed and, to be honest, SHOCKED that there was a single person in Japan who didn't at least recognize his face or music. XD