Basic information about the artist: https://polymetrica.wordpress.com/2009/11/10/yuugen/
Home page: http://yuugen.hiyamugi.com/
Myanimelist info: http://myanimelist.net/people/23317/Yuugen
Pixiv: http://www.pixiv.net/member.php?id=806502
Circle: http://www.doujinshi.org/browse/circle/24827/CASLTON/

I double checked for duplicates, but still, please, notify me if there are any I missed.
Images 001 and 010 were too big in png, so jpg versions were uploaded to the gallery, torrent contains originals.
Ordering is based on the width - starting from the largest.
Also, I did not include monochrome art from manga pages.

Galleries on ehentai:
/g/887067/e4b8970fd7/
/g/771459/0f5d995ef3/