The monster bits have to be for Alchemy right? I mean it's a classic trope of using monster parts and magic stones to make things like potions and magical gear. I imagine the author is going to introduce that at some point and is just laying the groundwork with the drops and the discovery of that skill. It was just weird that our antagonists didn't realize that considering how intelligent and methodical they have been so far with everything else. Anyways I love the dungeons in the modern day trope it is my favorite right now and of the manga that use it this is my favorite (it doesn't hurt that nightbug is incredibly consistent with his uploads). 🤩