What to read after Failure Frame: I Became the Strongest and Annihilated Everything With Low-Level Spells (Light Novel) Vol. 9?

Thanks to Mimori Touka's "worthless" skills, the Country at the End of the World is safe for now. Touka and his companions are sent to the Miran Empire as representatives to broker the new alliance between the two nations. But assassins are on their way to kill the Miran emperor, and one is a familiar face--Oyamada Shougo, ex-school bully and one of the classmates who abandoned Touka to his death. Will Touka finally have his revenge...?