Immortals

Origin
The first known reports of this species date back to about 550 BC in Asia. Beyond this, there are only theories as to their origin. It is known that parts of their DNA matches up with Human DNA. However, beyond this, little is known. There are theories that perhaps they are the children of Angels, but this is unlikely. Perhaps they could be a mutated subspecies of Humans? This would be plausible, but their DNA is too different to classify them as a Human subspecies.

History
The biggest historical significance that this species has, as a unified force, are the Persian Immortals. Yes, this was not just a clever name. They were Immortals. They were terrors of the battlefield, and it was not until gunpowder entered wide use that their effectiveness began to diminish, as it was possible to actually kill them at that point.

Beyond this, there are several instances of elite warrior being Immortals, as well as several programs aimed at capitalizing on their immortality.

Appearance
All in all, Immortals appear as Humans. They have the same body parts and general look to them. However, one will note that Immortals never have scars or deformities. They tend to be a bit shorter than the tallest of Humans, barely reaching about 6 feet at the tallest.

Behavior
Immortals tend to fill the more extreme niches in society. They are either extremely successful businessmen and women who have little regard for the world and life, or reckless and insane, looking to experience anything and everything. Some others are known to give up on life entirely, seeing it as pointless and painful, and instead seeking ways to end their own.

Abilities
The main power of Immortals, lays in their ability to simply survive. They have insane regenerative abilities, being able to regenerate organs in seconds, limbs in minutes, and most of their own body within an hour. They can even regenerate their own soul! This is largely why one will never see an Immortal with lasting scars. Their bodies heal completely. They also cannot die of old age, due to their bodies being able to regenerate and replace all cells in their body. Physically, they do not age beyond their late 20s to mid 30s, depending upon the individual.

Weaknesses
Beyond their regenerative abilities, Immortals are actually rather lacking. They are no stronger than Humans, no faster, and have no heightened senses. Their pain receptors regenerate as well, meaning that they feel all the pain again and again, no matter how many times they get hurt. However, it has been found that if the brain is not damaged, it can build up a high tolerance to this pain.

If an individual's brain is damaged or destroyed, it will regenerate, but they will lose all of their memories, with no way of getting them back.

Diet
Immortals do still need to eat, and will deteriorate if they do not. They cannot die from this, but it can leave them weak and helpless. Beyond this, their dietary choices are diverse, being able to eat vegetables, meat, and fruits with equal ease.

Lifestyle/Lifespan
Immortals can live forever, unless someone manages to kill them. They cannot die of disease, or normal injuries. It is not uncommon for them to start over many times however, with the destruction of their brain wiping away all of their memories. While most have adapted quite well to the changing times, others have been known to be stuck in the past, unable to understand new technologies and ideals.

Reproduction
Immortals are known to have one of the lowest fertility rates among all species. At about 2%, this species barely ever has growth in its population. But with a population that also rarely loses any of its individuals, why would they need it? Beyond this, they have been found to be able to reproduce with almost any species, with the child having a 50/50 chance of being an Immortal, or the other species.

Death
While it is very hard to kill an Immortal, it is not impossible. Destroying both the brain and heart of an Immortal at pretty much the same time will kill it forever. However, with there being so little death among their population, there is no information on where the soul goes after death. They cannot die of old age, disease, poisoning, or anything else that does not directly destroy the heart and brain.

Ranks
Rank E - Bystander - Having no combat skills, and preferring to stay out of the spotlight, these individuals do not make marks on history, instead preferring to attempt to live normal lives throughout the ages.

Rank C - Ageless - Generally, these individuals have had their memories wiped within the last century, and thus have limited combat experience. Nonetheless, they can be dangerous.

Rank B - Avenger - Possessing advanced combat skills, these individuals are able to match Veteran Huntsmen in single combat. Their rank name comes from tales of them biding their time for generations, biding their time for the perfect moment to get their revenge, or revenge for another.

Rank A - Time Lord - With countless centuries of experience, these individuals have perfected the art of combat, and are limited only by the limits of their bodies in speed and strength.

Rank S - N/A - While the impossibility of killing them may make them technically a match for an S rank, there are no Immortals who achieve this level of power.