As for your question waay at the beginning.. Serena was a Cappadocian, and their clan got wiped out somewhere in the Dark Ages, so she most likely suffered the final death. Etrius, being the second or third most powerful and oldest Tremere alive.. well you'd have a snowball's chance in hell to avenge Erik
He is probably alive and kicking, and still sitting around in Vienna
And that concludes our random VTM trivia