St. Germain's secret alliance with the vampires was the primary focus of the villainous actions, specifically him bossing Dragan around and being behind the funneling and subsequent siege/sacrifice of Castlevania's refugees.
There IS a story to be told about how the hell Hector was somehow able to connect with Varney and St. Germain, while also somehow knowing that Varney was not to be trusted, but that never got elaborated on. Though it did make for a laugh when Varney tried to recruit Isaac and ended up getting caller-blocked instead.