The two share a Rocket Raccoon/Groot, Jay Silent Bob relationship. Basically, he's the one who speaks at great length, and Dru's the quiet type, but the latter's much more reasonable and smarter than the other one. But that doesn't mean that one won't help the other. Zack treats Dru much like a big brother would a little brother, though with one exception: he doesn't pick on him like a bigger sibling would. Though there are times he will embarrass him, but Dru gets him back.
He loves Zahir's spontaneous side, as it always makes him laugh. He considers the two of them as the Wildcard Duo, since they're both unpredictable.
The daughter of the man who brought him back to life as a zombie. She finds him fascinating, but he keeps a good distance from her, in fear that she'll take him apart much like her father did when he was deemed a 'failure'.