Apocalypse Bringer Mynoghra, Vol. 4 (manga)

A seasoned gamer like Takuto Ira can draw only one conclusion from the inexplicable events outside Phon'kaven—he isn't about to go to war with another faction in a grand strategy game, but rather with characters from a roleplaying game. And while Atou is occupied on the Phon'kaven front line, their wicked (and peaceful) nation faces a surprise invasion! With only Isla and the warriors to defend them at home, can Mynoghra hold its own against an enemy from a different genre? The rules have changed, and the stakes have never been higher as GSG goes head-to-head with RPG…And one wrong move could spell doom.

Volume 4 of the Apocalypse Bringer Mynoghra manga series by Fehu Kazuno.