Just finished the volume and up until part 11 or 12, thought it was going to finally conclude. Instead...death. Sad, meaningless death.
Kudou got somewhat of a redemption. Based on his actions as the demon king, you couldn't really ask for a happy ending for him, even after finding out the motivation behind his desire to destroy the world.
But Berta's death was just pointless. It was a death she wanted and the best death she could have gotten, but it was still tragic and depressing.
And then we learned of the final days of the beast of darkness. After Berta's passing, I couldn't take the side story and had to walk away from the volume for a few days. Her viewing herself as alien and worthless...this almost feels like the Empire Strikes Back of the series.