Soul Magic is a rare Talent that deals with the soul. It is not strictly necromancy, and has nothing to do with the reanimation of mindless corpses, even though Soul Mages are often derisively referred to as such by the ignorant.
The aura color typically associated with Soul Magic is gray.
Perhaps the most spectacular spell only possible through Soul Magic is true resurrection. A Soul Mage can capture a departed soul before it goes too far, and return it to its body, although Healing Magic needs to be used on the body first in order to repair whatever it was that killed the subject in the first place. Most Soul Mages can only perform such a resurrection if the body has not been dead for more than three days, as after that point, souls will generally have moved too far into the Ethereal Plane to capture again unless soul trapped first. However, a sufficiently powerful Soul Mage may even be capable of drawing back a soul that has been dead for years. Usually in those cases, a new body has been acquired or constructed for the subject if the old one was not properly preserved in magical stasis.
Related to resurrection, a Soul Mage can place a soul into another body. Possession tends to refer to a Soul Mage forcing their own soul into another body, living or dead, and taking it over. It is, of course, much easier to take over a body that doesn't have a soul in it in the first place, or only contains a non-sentient soul such as an animal.
A powerful Soul Mage, upon death, may even be capable of remaining in the Material Plane unanchored to a body, in the form of a wraith. From there, they can simply possess a new body of some sort and will be back in the action.
A soul trap is a vessel to contain a soul in order to prevent it from moving on. This can be useful if one is intending on attempting a resurrection later but can't do it just yet, or if one is attempting to contain a dangerous being that normally will resurrect on its own, or continue to cause trouble after being reborn. A particularly malicious Soul Mage may soul trap an enemy to prevent their rebirth or torture them.
Usually objects like gems or crystals are used as soul traps. Casting a soul trap directly upon a subject's body will prevent them from dying no matter how much damage they take, but this is extremely difficult to do due to the malleability of flesh, but it will work if cast on a solid part of the body such as the skull. However, the limitations of consciousness still apply, and if enough damage is taken that the body no longer functions at all, it simply becomes a soul trapped skull, unaware as any other trapped soul would be.
A soul link or bond is a connection between two souls, allowing them to share mana, and sometimes other effects such as having access to inborn Talents or other unique abilities. In a typical situation, one party will be in a controlling position in the bond or link, generally the one who cast it. This allows them to regulate the flow of mana over the connection.
A temporary connection between two or more souls is called a link, and is often used in circles for ritual magic. They are quickly formed and immediately broken once the ritual is complete with no ill effects to any of the involved parties.
Bonds, on the other hand, refer to permanent connections, or at least ones that are much more difficult to break. Soul bonds are often used in demonic pacts. People enter into demonic pacts in order to gain power that the demon shares with them, in exchange for allowing the demon to use their own power. These deals are often extremely one-sided, and almost never does a demon choose to share all of their power with anyone. Furthermore, being in a controlling position in the bond, a demon can even shut down the subject's use of their own magic.