[quote=@Guardian Angel Haruki]
[@Fading Memory]
Out of curiosity, and possibly to compose a post to give an in for conversation, would it be possible to roll for Research into the Rot as a Downtime activity? If so, what skill should I roll for? 
[/quote]

Amaryllis has several avenues that would each confer Advantage for different reasons entirely based upon her preference for performing this research;

Going to the Fenhall Palace and asking for permission to view their Library...

Going to the Noctem Shanty outside of town and asking for their insights...

or Going to the Grand Temple and asking the priesthood about it.

Where you go will only influence which of the relevant information tidbits I have you get 'first' if you don't roll sufficiently well to get 'all of it'; the Clergy will prioritize the religious information, the Noctem will prioritize tangential information, and the Fenhall Palace will prioritize the Dale-Folk centric history of the subject. If any of those catch your eye, let me know which one you're relying on for your Advantage then roll me an Investigation Check.