In the Land of Leadale, Vol. 8 (light novel) — Ceez

Cayna finally interrogates Opus, who's been busy with various clandestine activities. He tells her that during the Game Era, Event Monsters in the Brown Kingdom broke out of the system and took corporeal forms, resulting in a mass monster propagation. Those monsters have since been sealed away in an Isolation Barrier, but Opus can tell it's deteriorating...which is why he's been searching for other former players reincarnated in this world. In order to protect Leadale, the players must gather in the Abandoned Capital for one big, decisive battle!