There isn't a strong tradition of classical zombies in DARK•HERITAGE so I don't expect them to feature much. Undead in general become much more singular, or at least very rare, in this setting, then they would in, for example, a typical D&D style fantasy setting. But, I'm a huge fan of the concept of undead in general if done correctly (which usually means sparingly.) Of course, your typical zombie appearance is anything but sparing; they've become highly correlated with concepts like zombie apocalypses, where zombies are running around all over the place. Individual zombies are rarely meant to be frightening; it's rather the vast horde of them that leads to the survival horror instinct.
To be perfectly honest with you, I have no use for this type of zombie. Foot-soldiers of the undead, if you will. Cannon fodder. Those are attributes that stand in direct opposition to the notion of zombies that are actually terrifying in any way.
Zombies in DARK•HERITAGE are known from ancient rituals passed down through the Tarushans, where a type of semi-legendary Tarushan wizard or warlock known as a bokor (or boccori in the Terassan tongue) would raise the corpses of the recently dead to be his slaves. This practice apparently persisted into fairly recent times, and Terassan academy scholars have theorized that these so-called zombies were never truly dead at all, but were instead drugged into a state of near-death, buried alive, and retrieved by the boccori. The boccori then used a combination of cultural indoctrination and forced drugs to keep them susceptible, paranoid and compliant. This debunking of the zombie myth by Terassan academics has been touted as triumph of the rational over the superstitious, and most Terassans (at least, if not necessarily Tarushans) believe that the zombie myth is just a myth.
Heriberto Òvest is, of course, a play on words of Herbert West, the titular character of Lovecraft's story Herbert West - Reanimator. This story is itself a pastiche, of sorts, of Mary Shelly's Frankenstein.
Zombies in DARK•HERITAGE are therefore more like flesh golems of D&D lore than the monsters that are called zombies. If using a d20 variant to represent the setting, that would be your best bet to recreate them. The m20 rules include both flesh golems and zombies, but those are just (basically) cut and pasted from other sources. I'm not quite sure what, if anything, the zombie stats would represent other than perhaps the very early boccori type zombie, which should be nonexistent at this point in the setting.