Alucard and Lenore begin contact due to rumors of the sultan of the Ottoman Empire being more ambitious and having a vampiric backer that is helping him win campaigns. Venice is a potential target, and Lenore would appreciate that not happening, thank you very much.
Introduction of friend Melchizedek, who offers the following: The silver one, our redeemer," Melchizedek says, picking up the skein of it like reciting the next line of a poem. "Kekazu whose heart is amber. He pours the light into us. He consumes the darkness from our flesh. Kekazu, kekazu. Aiiiiiiiiiie! [thread spot] and mentions the Cataclysm for the first time
Melchizadek also gives Lenore a dodecahedron, which is a range finder of sorts. It is powered by: you need to imbue a specific command or purpose into it - that'd be why you knew it as a range finder. That is the most common use. You meditate thoughts of navigation and location and finding into it, and then the connection lasts either a lifetime or until a more powerful will breaks the connection.
Lenore explains the Cataclysm: "The theories about the Cataclysm--which, again, no one wants to talk about at all, ever--fall into three camps. Either vampires were all wiped out and re-emerged again by whatever evolution created us in the first place, or vampires only ever evolved after this event. The most popular theory is that one vampire--the Ur-vampire--survived, and is then the father or mother of all vampires who have come after. But in any case, there seems to be a catastrophic event or events which results in a great loss of language and technology, which no more than one vampire survives. And this event or event involves at least one ziggurat, a flood of some kind, and possibly a rainbow."