Shuumatsu no Valkyrie - Jack the Ripper Case Files Shuumatsu no Valkyrie - Jack the Ripper Case Files is a spin-off Japanese manga series written by Takumi Fukui & Shinya Umemura and illustrated by Keita Iizuka. In 1888, London is the scene of a series of murders of prostitutes, commonly known as "Jack the Ripper". That day, the killer goes out to town for his next victim... The past of Jack, the English gentleman who represented the human side in the fourth round of the final struggle between God and mankind, Ragnarok, is finally revealed!