nanakura_nanane
Artist, illustrator.
Japanese name: 七座 菜々音 (reading is given as Nanakura Nanane)
The other names: せいこ (Seiko), ななくら (Nanakura), "877", 黒豆七 or 七曜 紫
Site name: 『 』 (Shiro Kakko, lit. "quoted whitespace")
Circle name: さんだいよっきゅう (三大欲求, SandaiYokkyuu)
(Actually, SandaiYokkyuu is the name of Nanakura's fictional Idol Unit. Fuguu-chan is a member of this group.)
Old circle name: しろかっこう
Old site names: sirosimi, 白紙魚、 or 白紙魚。
Old name (unconfirmed): はじめしん