I have no idea about what Jack and the author are plotting for the sequel, but there is a comment I would like to add.
In this debate, everybody is assuming that Zeal is the "good guy", so if he asked you to kill the vampires, they must be evil for sure...
Am I the only one who had chills down his spine all the time I was dealing with Zeal? I mean, I had the REALLY strong impression that in his mind he was thinking something of the kind "Nice fools, help me get rid of all my possible enemies, so that I conquer Everburn Mountains and in the sequel Jul and I are going to tear the world apart... MWHAHAHAHAHAAHAHAHAHA"
If Zeal would in fact be the next ultra-villain, then a lots of things would become clearer, including why he would ask you to slaughter some innocent bystanders... And this would explain also why, despite being super-creepy, he is my favorite Loren character: I have a soft spot for super-bad villains!