Velsper, also known as Welsper, is a demon, who is in a doublet, a link of fate established to preserve the balance between Heaven and Hell, with Belldandy. The doublets normally forget each other, but Velsper cursed himself to remain in child form in exchange for remembering his encounter with Belldandy. The curse could only be broken if Belldandy speaks his name. It turned out that his body could not handle his growing power, so he worked to break the curse by stopping time. After installing a virus in Yggdrasil, he ends up having the curse broken, and returns to the demon realm. However, because Velsper hacked into Yggdrasil, he was punished afterwards by being reincarnated into a kitten. He is the only demon who shows a Tsukaima (demon servant), having it obtained by Keiichi after neither him nor Belldandy could handle the burden of bringing the creature which almost transformed her into a demon because of Hild. His black fur becomes white spotted, but he returns normal after naming his Tsukaima as "Die Wespe der Blauen Lanze" ("The Wasp of the Blue Lance" in German).