Dying corals.
Yep.
Honestly, Luca wouldn't have even noticed it if he hadn't been particularly scanning the area for his precious oysters.
Then again, even if he had seen such a thing, most people, especially those around him, wouldn't have had any idea what was happening.
And yes, that would've applied to him too if not for a particularly memorable experience he once had back in Tesseris.
There was a time when certain kinds of corals were rumored to enhance the efficacy of pills. As one might expect, the people who wanted Luca to produce even better guiding pills demanded that he use those corals as ingredients.
Now, the little guide didn't really have much of a choice back then. Despite the fact that the best way to produce a better guiding pill was actually to avoid other ingredients entirely, he still had to produce pills that were allegedly improved so they wouldn't discover his secret.
