Re:ZERO -Starting Life in Another World- Ex, Vol. 4 (light novel) by Tappei Nagatsuki
Amid the upheaval after the royal line of Lugunica was broken, the Knights of the Royal Guard are sent to protect an envoy to Volakia, a violent empire often in conflict with the kingdom. Julius, Ferris, and Reinhard are part of this mission, but what will they find there...?