Tokyo Ghoul
In 2013, a prequel spin-off manga titled "Tokyo Ghoul [Jack]" was released on "Jump Live" digital manga. The story spans 7 chapters and focuses on Arima Kishō and Taishi Fura 12 years before the events of "Tokyo Ghoul". The manga features several characters from the main series including the above stated Kishō Arima, Taishi Fura, and future key characters Itsuki Marude and Yakumo "Yamori" Ōmori. It was compiled into a "tankōbon" volume published digitally by Shueisha on October 18, 2013.