Linen is a character design by Osamu Sato. It first appeared during the promotion of LSD: Dream Emulator and has continued to be used in most of Sato's modern-day work, even as the face of the independent label Linen Records.
"Linen" (リネン,りねん) has the same pronunciation as the Japanese words "philosophy" (理念) and "reason" (理ねん). One theory is that Linen has come to represent Sato's artistic philosophy.
Please note that this list is incomplete.