Konosuba: God’s Blessing on This Wonderful World!, Vol. 8 (manga)

After declaring that she wants to bear Kazuma’s child, Yunyun reads a startling letter addressed to her designated baby daddy and runs off to Crimson Magic Village!
Kazuma and the gang give chase, but the way to the village is packed with monsters-many of whom are looking for mates! By the time they arrive, Kazuma may end up with more children than he bargained for…powers, and I’m going to get to the bottom of it…