Vampire

Vampires (ヴァンパイア) refers to a race of immortals with an affinity for blood and the night.

Types of Vampires
In Overlord, the author seems to set tiers for vampires:

True Vampire: Shalltear's race. Looks like a monstrous undead with very few human qualities. Among the most creepy-looking vampires of YGGDRASIL, true vampires are even uglier than the others. Resembles a lamprey.

Origin Vampire:

Lesser Vampire: Reanimated by other vampires' race traits. They are rather similar to zombies in that they possess minimum intellect.

Vampire Bride: The only kind of vampire that looks beautiful but deadly yet their combat abilities are low.

Vampiric Beasts: Animals with the characteristics of vampires. Shalltear summoned some of them by her skill.
 * Vampire Wolf
 * Elder Vampire Bat
 * Vampire Bat Swarm

Appearance
Most of the vampires in YGGDRASIL are far from the modern 'aristocratic, mysterious race' archetype of vampires. Instead, they look like a horrible mix of bat and human. Shalltear's beautiful appearance is just a result of customization by her creator.

Abilities
Vampires possess numerous special abilities, including powerful muscles and fast regeneration. As undead creatures, they are effectively immortal. Noted for their longevity and taste for blood, they are considered deadly heteromorphic monsters.

Basic Vampire Race Traits

 * Fast Regeneration
 * Evileye of Temptation
 * Life Absorption
 * Create Lesser Race by Bloodsucking
 * Weapon Resistance
 * Ice-type Damage Resistance

Weaknesses
Despite their staggering advantages over humans, vampires are not invincible and can be slain through a number of means.

Basic Vampire Race Weaknesses

 * Slow movement penalty during Sunlight
 * Vulnerability to Silver weapons (only lesser vampires)
 * Added damage by Positive Energy

Trivia

 * The official manga divides the main vampire hierarchy into three categories: Vampire, Origin Vampire and True Vampire.
 * In the Web Novel, a Vampire's basic difficulty rank is 60, which is equal to upper A-class (almost A+). However, it is said that A-class adventurers can be confident of victory, while B-class adventurers might be able to win with appropriate preparation.