yuu_(kyuutai_kansetsu)
Artist who has three (or more) nicknames.
Nickname(1): 硝子屋 裕 (Glass-ya Yuu) (reading is a best guess)
Nickname(2): ゆう or ゆう。 (Yuu)
Nickname(3): 球体関節 (Kyuutai Kansetsu) or きゅうたい (Kyuutai)
Other names/IDs: 硝子, maclo, bisque_doll, oohashiyou
Circle & site name: 硝子電球 ("Glass Denkyuu" or "Glasslamp")