1451 DR
The eruption of Mount Hotenow devastated the surrounded region, and caused thousands of deaths. Some smaller settlements, like Thundertree, were completely wiped out by the cataclysm. The biggest nearby town, Neverwinter, also suffered great destruction, and many inhabitants lost their lives in the incident.
Castle Blackwater
No one knows how Castle Blackwater could have survived the eruption that killed thousands and destroyed entire settlements, while being so close to its source. While seemingly not harming the castle, it must have had an impact on the family, as it was never the same since. After leading their citizens well for years, the family retreated from the public eye and kept to themselves, causing many to believe them dead.
DM Note
When the eruption of Mount Hotenow happened, Arkus, by now well-versed in the occult, cast a barrier spell around his domain to shield it from the elements. This was made possible by his extensive research on the harnessing of power from gems. During the aftermath, he discovered that a new kind of gem had been brought close to the surface due to shifting of the earth. He named this new, pitch-black material ‘Blackstone’, and promptly began researching their capabilities, convinced they were a gift from his otherworldy ‘master’.