The Curtis vampire world takes elements from a few sources (White Wolf, "Children of the Night" by Dan Simmons, and Underworld), and some original elements, namely the retrovirus decay, the power levels and interaction between the 5g and 6g, and the absence of newly sired powerful vampires.

Calling vampires in this setting "undead" is inaccurate, as they do not die when they are sired. Their bodies, while functioning differently than when they were human, are still alive. The heart still beats, the lungs still take in air... occasionally.

The origin of vampires is unknown, and all of them living today have been sired. Siring involves biting humans and infecting them with the vampire retrovirus. The virus is magical in nature and causes supernatural changes. It is only transmittable from a bite, lasts in a host's body for his entire life, and the infection rate is 100%. After being bitten and infected, the human falls into a coma for a few days and awakens as a vampire, slowly learning to use newfound strength, speed, and any special abilities they will have.

Siring is usually done only by those vampires who have gone insane, or by those who have secure strongholds and wealth. The biggest problem with siring is the risk of exposing the existence of vampires. Newly sired vampires usually are a mass of psychological problems until they adjust to their new life. Many succumb to bloodlust and start killing at random, some venture out into sunlight to commit suicide. Vampires of limited means and sound mind do not sire.

The vampire virus is responsible for the initial change only. After the initial change, the new body does not require the virus to maintain any special abilities. The new body (other than the 6g exception below) sustains itself by blood alone. Normal food and drink can be eaten, and has no health effects or consequences. Blood of humans and predator mammals is best for rejuvination, but any blood will do.

The virus degrades over time in both specific and in random ways. The degradation accelerates over time, and it is estimated that it will decay completely within the next century. Initially (see timeline below for specifics), all sired vampires were equally powerful and had the same set of abilities. Later, around the time of Christ, newly sired vampires were not as strong, and lost some abilities. Around 1200 AD, the virus decayed more randomly, and different bloodlines contained different sets of standard vamp abilities.

Since 1800, newly sired vampires are easier to kill, and have almost no supernatural abilities other than enhanced strength and speed. They also age, albeit much slower than normal humans. Vamps sired since 2000 have more in common with humans than with older vamps, and are less alergic to sunlight.

Sunlight is the big killer. It is assumed vampires are demonic, and this is proven true through their reaction of profound grief and rage (and in the case of older vamps, insanity) when confronted with true sunlight. Sunlight will burn and kill all but the newest vampires. Older vamps have stronger reactions to sunlight.

They do get pale if they don't feed, and bloodlust will eventually overcome them. They don't go into "torpor" if they refrain from (or are kept from) feeding, they just die from starvation. They do need to breath, but not much.

The other standard mythological elements are untrue. They cast a reflection, many enjoy the taste of garlic, some pray to the Christian God and wear crosses. Most don't sleep in coffins, although they come in handy to avoid the sun when traveling. It's a matter of taste, really. They don't have to be invited to come in.

Vampire Generations:

There are 6 distinct generations. A vampire's generation is not determined by what generation sired him, but what time period he was sired in.

All generations have super hearing, night vision, and slowly increase dexterity
and speed to inhuman levels (2g = Flash, 3g = Spiderman, 4g = Batman). All can eat food
but get no sustenance from it. Vamps made from more degraded virus require more blood.

First gen (1g) = 15,000 BC (end of last ice age, first agriculture)
Power level unknown, rumors of "super demons"
All killed off by unknown means

2g = 4,000 BC (Mesopotamia, beginning of recorded history)
Demonic. Immortal, shapeshifting, flight, hypnosis, inhuman strength
Spellcasting, invisibility, desolid through dirt
Organ and limb regrowth, cut off head to kill, staking heart has no effect
Sunlight causes instant death (spontaneous combustion)
Few living, locations unknown

3g = 1 AD (Birth of Jesus)
Dracula. Immortal, shapeshifting, flight, hypnosis, super strength. Some spellcasting.
Organ regrowth. Cut off head to kill, staking disables until stake removed.
Sunlight causes insanity and permanent burns
Sustained sunlight will kill in a few seconds
About 25 living, most in hibernation or reclusion

4g = 1200 AD (Crusades, Marco Polo, Ghengis Khan, Dante)
Highlander. Almost immortal (ages 250 to 1), olympic powerlifter strength.
Most have one special ability (flight, hypnosis, shapeshifting), some have two.
Cut off head or stake to kill.
Sunlight causes extreme grief and depression
Sustained sunlight burns and will kill in less than a minute
Roughly 100 worldwide, most rich and secluded.

5g = 1800 AD (Napoleon, early United States)
Bodybuilder. Ages extremely slowly (50 to 1), bodybuilder strength. A few have one
special ability, but most do not.
Cut off head, stake, or cause massive internal damage to kill.
Sunlight causes depression and loss of focus.
Sustained sunlight burns and will kill in a few minutes.
Roughly 500 worldwide. Most have to move around constantly because of blood demands,
some form havens using 6g vamps as daytime guards.
Cannot sire.

6g = 2000 AD
Healthy normal. Ages moderately slowly (5 to 1). Stronger and faster than an average
person. No special abilities.
Colorblind.
Slightly harder to kill than a normal person.
Sunlight has no immediate effect.
Sustained sunlight causes delayed reaction times and mild stupor.
Requires both food and blood for sustenance.
Most have various nervous habits.
Roughly 100 worldwide. Mainly employed as guards for 5g hideouts.
Cannot sire.

Character of the vamp world:

The increased blood need for 5g vamps, the state of 6g vamps, and the deterioration of the virus are the main issues of interest in the vamp world. Most earlier generations are disgusted by 6gs due to their weakness. Some hunt them down to prevent exposure of the vamp world because of vamps who hunt in daylight hours.

5gs have an interesting relationship with 6gs. 5gs employ them to keep people away from their hideouts during the day, and in return give them some blood from their previous night's prey. 5gs treat 6gs as if they were lower class, such as slaves, pledges, or probies. Because of the 6g tendency to fall into a stupor when exposed to too much light, many 5g vamps assume they are retarded or just stupid.

Some 6gs resent this treatment, and try to kill their employers. These are quickly hunted down and killed. Others pursue night-time jobs (money to buy food) so that they can retain their mental edge. Ironically, most end up in jobs such as bouncers and night security guards, jobs to which they are well suited due to strength, agility and enhanced senses, but mainly because they ensure night hours.

5g and 6g vamps can't sire, and since all new vamps will be 6gs, siring has gone out of style and is a very rare event.


Psychological Vampires::

These are diametrically opposed to the vampires above, and both should not exist in the same fiction world. Psych vamps are a shadow incarnation, birthed by a mentally disturbed religious or spiritual zealot in an event similar to a stigmata. Their natural form represents a monstrous archetype of their creator, but the vamp's intended victim usually does not see them this way until it is too late. They feed off of the spiritual/emotional energy of people. They are single-minded, and not fully sentient, patterning their behavior based on the expectations of the intended victim.

Psych vamps appear as the victim's ideal of someone dangerous and alluring. They attempt to lure them away from safety and drive them mad and eventually to suicide. Strictly speaking, they don't exist in the real world, so you will never see them opening doors, bumping into people, or manipulating objects. They cast no reflection, which is the main clue that your psyche gives you that they aren't real.

Their hold over their victims comes from what the victim desires and will allow. They must be accepted, they can never attack someone who resists. They must be invited in. They respond to whatever the victim believes, so artifacts of faith (crosses, holy water) and exorcisms have the intended effect on them, provided the victim believes they will.