The Aldarri
An Aldarri, in its natural state, is a small humanoid looking creature, standing about 2 inches tall, with smooth red skin, sharp clawed hands and feet, no hair, mouth, nose, or ears, and slighlty large (for their size) totally blue eyes. They are extremely susceptable to the elements, and in fact will die within an hour from being exposed to the outside world. However, this is not (much of) a hinderance to them, because the Aldarri are a symbiotic race, and live within the bodies of other creatures. They are generally quite intelligent, and all have a few Psi abilities, though not the same kind as most races with Psi have (explained below). They need to be within host bodies not only for protection, but also to absorb nutrients from them, as the Aldarri do not eat. An Aldarri enters and leaves a host body by literally clawing through skin and tissue, however this does not cause pain or damage to their host because the Aldarri secreet from their skin chemicals which totally numb the pain and cause the host's body to heal pretty much instantly after the Aldarri has passed through. Aldarri generally each have their own personal hosts, with a few exceptions where a parent and child are temporarily living in the same host (explained further below). They tend to only take mammalian hosts.
An Aldarri has a "telepathic" link with it's host's brain while inside the host. The link is not actualy telepathic, but since the way it is achieved is not really known, it is referred to as a telepathic link. The link allows communication between the host and the Aldarri (if the host is sentient), allows the Aldarri to gain knowledge about the host by actually playing back its memories and reading it's mind, lets the Aldarri sence everything its host sences, and even allows the Aldarri to control the host's body. An Aldarri, after being within a host for a good period of time, can use a combination of chemicals they secreet and Psi to make genertic alterations to the host's body, the magnitude of which depending upon how readily the host body can except genetic alterations. They can improve their host's strength, speed, immune system, healing rate, sences, and even make alterations to the host's body structure such as adding/subtracting limbs (such as wings), changing the shape or function of limbs (such as making hands into sharp claws), or even just a minor change to alter the host's general appearance (they can also even copy the appearance of another of the host's same species). However, the more complicated changes, such as any change at all to outward body appearance, are not automatically known to the Aldarri, and must be learned, or developed through experimentation. Luckily, an Aldarri can (usually) reverse any changes it has made to it's host. It should also be noted that an Aldarri has the ability to keep it's host from becoming pregnant/making someone else pregnant (depending on the host's gender), or help it along.
The exact way Aldarri reproduce is not known, since they do not like being experminented upon or observed in lab conditions, nor do they discuss it, but it is known that Aldarri do have gender. Their body shape tends to resemble either a male or female human, depending upon the Aldarri's gender, and even the telepathic voice that an Aldarri communicates to its host with reflects its gender. However, host selection is not dependant on gender; there are many cases of male Aldarri with female hosts and vice versa. When Aldarri mate, one Aldarri leaves its host and enters the other Aldarri's. The Aldarri then becomes non-responsive to any communication attempts made by its host, however extreme and nearly overwhelming feelings of pleasure are transitted uncontrollably into the host's mind. This goes on for about 2 hours, at which time the first Aldarri returns to its host, and the Aldarri who's host they were in becomes responsive again. The mating is usually successful, and the baby Aldarri comes into being (by whatever method) within a couple of months. The child usually lives with the mother in her host, but there have been cases where for whatever reason the child is moved into the father's. The parent then raises the child and teaches it what it needs to know for about 2-3 years, at the end of which time it has reached maturity, and is ready to find a host of its own.
The Aldarri are the only known sentient species of their homeworld that didn't move there from another planet, and the majority of of Aldarri have hosts that much resemble humans, except they are slightly shorter and a good deal weaker (in their natural state), which live on the Aldarri home world, which is very very much like Earth. These hosts are not in the least way sentient, and by some odd twist have no survival skills at all, so the Aldarri do truly have a symbiotic relationship with them. They gain a place to live and needed nutrients, while genetically improving their hosts and helping them survive. The Aldarri always are in control of these hosts, since otherwise they would pretty much laze about and do nothing. The host species has no name, and are often referred to as Aldarri by other species in the confederation, since most or all of them have Aldarri symbiotes, and just referred to as hosts by the Aldarri themselves. Some outisde species seem to not even realize that the Aldarri are actually symbiotes within the hosts, and not the hosts themselves, and in fact this was not known right away. The hosts' bodies are very accepting of most genetic alterations made by the Aldarri.
Not all Aldarri have the type of host described above. Since they joined the confederation, more and more Aldarri have taken sentient hosts. They are still in the minority, however there is a good deal of them. Many Aldarri actually feel lonely with their non-sentient hosts and often would much prefer to be the symbiote of a nice, sentient member of viable host species. However, an Aldarri never enters a sentient host without the host's permission. They also respect the privacy of their host as far as memories, and only read what memories the host gives them permission to, except in extreme or emergency situations. Generally, when an Aldarri has a sentient host, it either rarely ever takes control of the host, or the host and the Aldarri take turns being in control, depending upon what the host wants to do, but usually it ends up being the latter, at least after the host and Aldarri have become familiar with one another. Often times an Aldarri and its sentient host form extrememly close relationships. (After all, one is living inside the other's body; how much closer can two beings be? ;) ) An Aldarri and its sentient host often gain a few personality traits of the other, and most pairs share views and opinions on many matters. While a host dieing does not necessarily cause the Aldarri to die (see below), generally Aldarri who have formed a close relationship with their sentient host can not bear the loss of their great friend, and refuse to leave their host's body, dieing as well shortly afterward. However, it has been known for an Aldarri, if its sentient host was murdered, to try to get a new host simply to take revenge upon the murderer, though this is extremely rare. In every case where this has happened, the Aldarri then died after exacting its revenge. Generally, Aldarri who have a non-sentient host will attempt to escape and find a new host, though this is not always successful.
An odd thing about the Aldarri is their life span. If an Aldarri's host dies of old age or disease, so does the Aldarri. But if the host dies of unnatural causes, such as murder or a fatal accident, as long as the Aldarri itself wasn't physically injured, it lives on, and can find a new host, assuming it finds one before it is killed by being exposed to the outside world. Never has there been a case of an Aldarri dieing of its own old age.
The Zeldar
There is a genetic offshoot of the Aldarri race known as the Zeldarr. The only outward appearance difference between the two is the Zeldarr's eyes are always red rather than blue. They are very few in number, and their home is unknown. They are much like the Aldarri, except they are unable to produce the numbing agent the Aldarri can, so though they still cause no damage to a host by entering/leaving, it is extremely painful for the host. They do not care at all about their hosts, except for the fact they realize they need a host to survive. They genetically pump-up their hosts as much as possible, often going through a few hosts simply because they try to improve their hosts farther than the host's body can take, thereby killing the host. When they take sentient hosts, they dont get permission, freely read the host's mind, and are always in full and complete control of the host. They never, ever form any sort of emotional bond with their hosts, and if they can escape the death of their host, they will. They even go so far as abandoning and then killing a host at the first available chance should the host start to become ill or old. The Zeldarr do have a set life span, and die after 200 years, regardless of the health of their current host. The Aldarri and the Zeldarr are mortal enemies, simply because the Zeldarr go against everything the Aldarri stand for, and because the Zeldarr secretly envy the way the Aldarri get along with their hosts, and the way they seem to be able to live so much longer. While the Aldarri are quite obviously symbiotic, the Zeldarr are considered to be parasites.