The Undead are a rare sight, but tend to stick together and appear in great numbers. Opinions towards the undead vary from the total acceptance advocated by Sybil to the disgust Harry Moleman has and Flint Paper's inclination to shoot them on sight.
Having been separated from their souls, zombies' personalities run the risk of degenerating to the mindless brain-eating variety. Zombies can communicate with other zombies but not with the living; Agent Superball seems to be an exception, but he may be faking it. Bullets will only temporarily stop zombies, but they are otherwise no more capable than their human forms.
Vampires possess superhuman strength and speed (enough to catch a bullet), but are vulnerable to uv-light, holy water, garlic stench and a stake to the heart.