Konosuba: God's Blessing on This Wonderful World!, Vol. 5 (light novel): Crimson Magic Clan, Let's & Go!!

After Kazuma and crew's less-than-relaxing vacation, Yunyun burst onto the scene with shocking news-the Crimson Magic Clan is in danger, and she wants to bear his children to save it! Kazuma returns with her to the village, but the situation isn't quite what he expected...