Tokyo Ghoul: Void

Tokyo Ghoul: Void is the second novel set in the Tokyo Ghoul universe. The short stories take place during the six month gap between the Aogiri arc and the Raid of Kanou's Lab arc.
After the unprecedented raid on the ghoul detention center by the Aogiri Tree organization, the Commission of Counter Ghoul is working to tighten security across the twenty-three wards. However, some ghouls begin to cause unrest in the 8th Ward, continuing the cycle of retaliation between human and ghoul. And what of Kaneki after he left the 20th Ward? This second novel depicts the aftermath six months after the 11th Ward occupation.
(Source: Tokyo Ghoul Wikia)