The Sapper is a bossClockwork modelled after the Clockwork Burrower that plants explosives on the walls at the end of each day at Deception Pass, pushing back Kingdom Force and forcing Lock to rebuild the walls. Its battle is different from than most battles. Kingdom Force knights set up a trap to catch the Sapper, and Lock must defeat it before it escapes. The day is lost if Lock is defeated or the Sapper escapes off-screen. The day is won when the Sapper is defeated.