This vampire in particular might then have been surprised by the .44 in Harry's duster pocket. Magic was groovy alright, but he'd learned that mortals had some simpler methods for killing.
But the gun would have been less than useless against this vampire, which was why Harry had gone for the blasting rod instead. Fire was his weapon of choice against such creatures.
But now, it seemed, he would need neither.
The wizard's brow furrowed, unsure of what he was hearing. '...if you are here in the name of Hell...' Harry began to laugh outright at that. "No, man," he said, shaking his head. "Just your everyday wizard, looking to... well, preserve humans, I guess." He gave the vampire a curious look. "Don't take this as offensive, but... what's the catch? Trying to preserve your food supply? Or just don't like the competition?"
He'd relaxed further, once the vampire had given his word on the truce. Such old laws were the closest thing to unbreakable as they could be, within the supernatural world.