Arifureta: From Commonplace to World’s Strongest: Volume 6 by Ryo Shirakome

Hajime and his party are on their way to the Haltina Woods when they run into Heiligh's princess, Liliana. What she reveals shocks Hajime. Aiko, the teacher that Hajime owes so much, has been kidnapped. Hajime decides to alter his plans and run to her rescue. However, in order to save her, he'll need to first make it up the Divine Mountain. Awaiting him there is the toughest challenge he's faced yet: a battle with God's Apostle.