poru_(naasan)
Artist.
Japanese name: ぽる (Poru)
Old names: なーさん (Naasan), "na-san" or "masa"
See also
* Pixiv account: http://www.pixiv.net/member.php?id=6515792
* Niconico account: http://www.nicovideo.jp/user/5075425
* Niconico Seiga: http://seiga.nicovideo.jp/user/illust/5075425