maso_(ascii_art)
Artist, webmaster of his renowned webpage, 2ch全AAイラスト化計画 ("2ch's All Ascii Art Illustrations Project"). His art of Yukkuri Shiteitte ne gave it great popularity in the internet world.
Japanese name: まそ (Maso)
See also
* Home page: http://riceballman.fc2web.com/
* Nicopedia article(JP): http://dic.nicovideo.jp/id/4716874