Colosseum II

is the second volume of the Colosseum light novel series, written by Shinjiro Dobashi and Illustrated by Yukiko Horiguchi. It was released under the Dengeki Bunko Imprint in October 2015.

Synopsis
Being an outsider is no longer allowed. The second horrifying school survival suspense! The killing in a closed space involving Io Tsukishima was nothing more than an outpost! With the return of the surviving players, the death game "Colosseum" will enter a new phase. A new survival game with 1000 participants that involves the entire school. Whether to bond with classmates or to gather and pull out talented people-the reaction of school students including Yu Hagiwara who turned into a player's position in front of the two malicious options presented What? And the answer given by the returnees from the closed space of Io and others is-- !?

(source: Dengeki Bunko Official Website - Translated)