I'm Standing on a Million Lives volume 12

Powerful allies have stepped up to help slay the dragon--the Cathean monks, a band of formidable magic-users. Ozu, their leader, is off-the-charts in strength, something Yotsuya learns the hard way...but now he's sure this mission will be the easiest one yet. But little did he know that in short order, their only hope would be Futashige, locked in a basement dungeon... In a land where the workers are brutally oppressed, the most oppressed one of all is ready to rise up and punish the exploitative bosses of a whole other world...not to mention the Dragon Bishop lurking behind the scenes!