Artist, NicoNico video creator, best known for the artist's Touhou video series: Nise-Koumakyou
His fan-nickname, 友達が少ない人 (lit. "a person who doesn't have many friends") came from Rumia's quote in one of his videos: ”...Is that so? You have no other friends?”
Artist name: JACK
Fan-nicknames: 友達が少ない人 (Tomodachi ga Sukunai Hito) or メタルマックスの人 (Metal Max no Hito)