After the Cataclysm
The Blackwood Marsh is a huge stretch of murky swampland, generally avoided. Caravans passing by the marsh on the route that travels between Valmire and Praetos bring extra guards, as attacks by strange creatures are more likely.
The adventurers discovered a tribe of kobolds which seem to worship a dragon. After finding and defeating the dragon in what appeared to be a temple of some kind, they found a strange portal beyond the dragon’s treasure.