Vampire

Vampires are a race of immortal undead beings that were once Human until they were bitten and infected with Vampire venom. In order for them to survive they thrive on a living creatures blood, whether it being Human or animal blood.

After becoming Vampires, an individual's natural abilities are greatly enhanced and are also bestowed powers beyond the natural which grow stronger with time, which makes it difficult for a Human to defeat a Vampire.

Becoming a Vampire
Vampires have the ability to transform humans into their own kin with the simple act of biting them. Once bitten, venom from the bite spreads rapidly throughout the victim's body. A Vampire also has the ability to prevent the victim from becoming a Vampire by sucking out the venom, but must act quickly. The effects of the Vampire venom seems to be very painful for a human to endure, which causes them to twitch at a rapid pace as shown when Jesse bit Ethan inRe-Vamped. Can be really really painfull.

Fledgling
Even though a vampire can transform a human into one of their own by simply biting them, being bitten by a vampire only turns the victim into a "fledgling" - a being between vampires and humans. Fledglings are basically new vampires that have not tasted human blood yet, and thus have not become full vampires. They have mortal bodies and have a limited lifespan of 28 days unless they drink human blood to complete the transformation or their mortal bodies will die. However, they can prevent their deaths by drinking a magically brewed human blood substitute, which will keep them alive without becoming vampires. Fledglings that choose this way of life only have to drink the substitute occasionally and can drink animal blood regularly. They will still have a strong urge to drink Human blood. They can do certain things to dull the craving, an example is that Sarah was scarfing chips and other junk food in the episode Blood Drive.

Despite gaining vampire powers, fledglings are weaker than full vampires and will tire out faster than them. They also lack the ability to fly like full vampires and not as temperamental. Fledglings can only fly if they pay.. It's assumed by Sarah, that when a fledgling becomes a full vampire, he or she gives up any chance of regaining his or her humanity.

Full Vampires
Drinking the smallest amount of human blood will cause a fledgling to become a full vampire. Full vampires don't have mortal bodies thus become true immortals. The strength of their powers they had as fledglings will increase, as will their urges and temper. Vampires also obtain the ability to fly. To enter a residence, they have to be invited in first or else trying to intrude will sting/burn them. Vampires also get angry easier than fledglings do, and find it harder to control it.

Appearance

 * When Vampires are angry or are about to fight someone, they grow fangs and their eyes begin to glow a yellow color, in a similar way as cats and other felines do. Or they can become a dark blue-ish purple.
 * They have the ability to grow their fangs whenever they want, usually when they're trying to scare someone, show off, or about to bite someone.
 * Full Vampires have no reflection in a mirror and cannot appear on film (i.e. photos). Fledglings have a murky appearance in a mirror, but still cannot appear on film. The reason for this was later revealed to because, there curse blocks there soul, which is what appears in reflections or on film.
 * All Vampires have enhanced emotions.

Abilities

 * Superhuman Speed
 * Superhuman Strength
 * Superhuman Hearing
 * Healing Factor
 * Flight
 * Immortality
 * Hypnosis (Only old, powerful Vampires)
 * Telekinesis (Only old, powerful Vampires)
 * Superhuman Agility

Weaknesses

 * Sunlight - The sunlight doesn't kill vampires, but it annoys their eyes. They sometimes need to wear sunglasses and sunscreen in the daylight to avoid this problem.
 * Invites - Vampires cannot enter someone's home without being invited in first. It is a person's only safe haven.
 * Holy Water - Vampires turn to flames and get sent to Limbo when they get drenched in Holy Water. If they only get splashed a little bit with Holy Water, it just burns them but they survive.
 * Wooden Stakes - Vampires die when stabbed in the heart with a wooden stake.
 * Garlic - Vampires hate the smell of garlic.
 * Magical Daggers - Benny's grandmother gave Ethan a pair of daggers capable of killing vampires.
 * UV Light Sabers - Similar to the light of the sun, it has enough power to fight and hold off a vampire, but not enough to kill it.
 * Crosses but they just can't come close.
 * Spells just harm.

Vampire Limbo
Although Ethan, Sarah and Benny usually speak of "killing" vampires, it's possible that vampires don't actually die, nor even when a wooden stake sinks into their hearts. As Sarah said during MBAV Movie after she slays the vampire disguised as a pizza delivery guy, vampires are sent to a Limbo, where they stay forever, but don't die.

There could also be a way for vampires trapped in the Limbo to come back to the living world, as Jesse plans to revive his vampire army by using the souls within the Cubile Animus.

Also, although everybody thought that Jesse died- thus sending him to the Limbo-, in the episode Re-Vamped he finally could regain his physical form and came back to life.