1. There are records at other Warden bases. Their archives are less complete than the archives at Weisshaupt are (or were; see 2) and more likely to house books and documents that were either so universally important they were copied from Weisshaupt or so localized and unimportant that Weisshaupt didn't want them, but it would be plausible for some caches of obscure documents no one looked at very closely before to contain something interesting.
2. Weisshaupt would require a big undercover mission. The archives are also part of what burned in the fortress during the coup in the Anderfels (intentionally, to prevent leaving that information in enemy hands). The destruction likely wasn't total before someone intervened, but the archives will be a lot less extensive than they might have been before that. Whether it's a mission that's worth the risk is something we'll leave up to IC leaders to decide ICly.
3. Riftwatch does have access to Inquisition records. It'd require actually going to Skyhold, but they'd be allowed, and handwaving some correspondence with Inquisition archivists is fine.
4. The Wardens don't have any reliable methods for dealing with corruption. Cleansing runes are a known entity that can hold back the spread of corruption on surfaces, discourage red lyrium growth, etc., but would not necessarily outright cleanse anything that was already corrupted. There are also a few odd incidents in canon and game history that Ellis could find out about:
Fiona was mysteriously cleansed of corruption while pregnant (with Alistair—sorry to stick my character into this, -MJ). She gave birth in Weisshaupt and was there for a while afterwards while they tried to figure out what had happened, so there may be more records related to that.
A group of Wardens who interacted with the Architect had their corruption accelerated, causing most of them to progress rapidly toward their Callings; one of them (Duncan) had a pair of enchanted daggers that somehow prevented him from experiencing the same effect. One of those daggers is somewhere in Riftwatch's storage rooms now.
Within Inquisition/Riftwatch records, there might also be mention of Merrill cleansing an eluvian of the taint. (Merrill's method for cleansing her eluvian was based in part on Dalish magic that can slow the taint's progression in individuals—for example, long enough to delay someone's transformation into a ghoul so they can be transported to undergo the Joining—so there may also be mention of that Dalish magic in Warden records, separate from anything to do with Merrill.) Merrill was able to combine this with blood magic to the point that it cleansed the eluvian entirely.
Merrill and some Wardens subsequently used the same ritual and a great dragon's blood to cleanse a Warden (Nathaniel Howe) of corruption and "cure" him.
no subject
2. Weisshaupt would require a big undercover mission. The archives are also part of what burned in the fortress during the coup in the Anderfels (intentionally, to prevent leaving that information in enemy hands). The destruction likely wasn't total before someone intervened, but the archives will be a lot less extensive than they might have been before that. Whether it's a mission that's worth the risk is something we'll leave up to IC leaders to decide ICly.
3. Riftwatch does have access to Inquisition records. It'd require actually going to Skyhold, but they'd be allowed, and handwaving some correspondence with Inquisition archivists is fine.
4. The Wardens don't have any reliable methods for dealing with corruption. Cleansing runes are a known entity that can hold back the spread of corruption on surfaces, discourage red lyrium growth, etc., but would not necessarily outright cleanse anything that was already corrupted. There are also a few odd incidents in canon and game history that Ellis could find out about: