This was once the headquarters of the Zhentarim Alliance Kerslin Castle
Kerslin had sacrificed every single Adept in the castle through a blood ritual after the war between the Crimson Clan and the Jorma Clan. Even the Fourth grade Adept leader of the clan Adept Freed had been sacrificed. After devouring so many adepts, including the advanced Fourth Grade Freed and seven Third Grade adepts, Kerslin had reached the level of a forbidden lifeform
Kerslin had possessed the power of a beginner Fourth Grade prior to its blood ritual. After the ritual, Kerslin had managed to reach advanced Fourth Grade
It then forcibly embraced by the Fourth Grade Vampire Adept Mary and became property of the Crimson Clan