"Kono Subarashii Sekai ni Shukufuku wo!" (bless this wonderful world!) volume 13 by Akatsuki Natsume. This volume features a giant turtle and a marriage proposal.
The giant turtle is a moving island of treasure, reminiscent of the opening scene from season 2 of the Konosuba anime, but it's actually a very different quest. Given the usual flow of events in this series, I would have expected this to not go very well and maybe have Kazuma die once or twice before the end of the chapter, but actually it was a successful quest from beginning to end. It is quite unusual for Konosuba where everything went exactly as planned.
Near the end of this book is a more typical fantasy battle, with ice magic from With matched against the fire magic from Duke. This typical battle is also a slightly unusual event, and addresses Kazuma gripe at the end of the first chapter on the lack of typical fantasy quests in this world. Of course it started due to a vast misunderstanding and ends in the usual comical fashion.
Besides these typical battles and quests, everything in between is the familiar Konosuba staple, including Aqua's second line of figure merchandise, Aqua's misguided gardening hobbies, Aqua's trauma with frogs, and Aqua's surprising talent in befriending a stranger. This volume is all about With, but Aqua got all the spotlight. Unrelated to those, my favorite highlight from this volume was Kazuma's inner thought: "are we the baddies?"
Hopefully Yunyun will get all the spotlight for the next volume.
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Next (2018-02-20): Legend of Zelda: A Link to the Past