If you are not buried, eaten or burnt, you come back as an undead monster after a number of days equal to your POW at the time of death. If your body is still intact, your soul is still attached to it. Depending on how you died and what kind of person you were, you may become any one of hundreds of types of undead. These creatures are known as "shur" by the Kadiz and Hill People, a term that means "ghost".
If you are eaten, you are dead permanently. Your soul drifts along on the wind until it passes into an embryo, probably of an animal, whereupon you are reincarnated. Along the way it may drift into other loose souls and merge or entangle with them. You do not remember your previous life once you are embedded in a new body, and the only way to release your soul from its new home is to kill your new self. This drifting process means there are almost always animal souls around for shamans and summoners looking to bind them.
If you are burnt, your soul flies off into the sky to join the stars. The more powerful the soul, the brighter the star. The divine heroes of Dwer Tor automatically explode on death in a burst of heat and light to ensure their return to the sky. Most everyone else needs a pyre. This is most common amongst the Dwer, particularly optimates and thaumates; for priests of the Celestial Herd, and members of various stellar cults like the Leper Star cultists.
To bring someone back to life who is a star in the sky is a known process, albeit one that rarely succeeds. The summoner must know the person's real name, must build a fire, and must write the summons on a piece of paper in red-black ink made from iron and rust which is then burnt in the fire. They must then invoke and venerate the person to be resurrected. This has a chance of working equal to the POW of the dead person divided by 10 (round down). It can be performed once per person per death. A few other methods are known to exist with better chances, including the method the Dwer use to summon their divine heroes back to earth, but the exact steps and materials are secrets. The Dwer would readily kill anyone attempting to study their techniques. Most of the alternate methods are extremely bloody, and involve sacrificing and burning humanoids.
People brought back to life by this method reappear as falling stars somewhere in the Dawnlands. There is no guarantee this is anywhere near the summoner, though the trajectory can be tracked and plotted by expert astronomers. When they return, they have any gear that was burnt with them. The sins of their previous life harden and encrust around them as they return to earth, and these break off and become aberrations, often intelligent and always hostile to the returner. These slither off to cause trouble unless the returner or anyone else nearby can stop them.
If you are buried, either underground or dumped into a water source, your soul enters into the dream world (which is often also called the "underworld" for obvious reasons). This is the most common fate for people who die in the Dawnlands. Getting out of the dream world and back to life is easier than coming back from the stars, but is significantly more dangerous both for you and other people. All that is required is for a priest to cast the spell Otherworld Journey, or for a shaman to enter it through meditation. Then they simply need to find you, and take you back to where they entered from. If this can be accomplished successfully, you appear buried in the ground at their feet, and can be dug up (it helps to have a team of people prepared to dig you up so that you don't suffocate and immediately sink back into the underworld). You reappear with any gear you were buried with.
The problems with this method are mainly finding where the person is and dealing with the denizens of the dream world, many of whom are hostile, powerful and hungry for the souls of travelers. As well, your old body normally becomes a ravenous undead monster that attempts to dig itself out of the ground and consume your new body. All the goods that were buried with it remain there (what you bring back are solidified dream-copies of them). Souls are typically located in the parts of the dream world that belong to the gods they worship. Forest People are typically found as insects in the Hivehome, Hill People and Kadiz roam the open plains as wolves following the Stone Pack, Dwer helots swim as fish in the Great Sea, and the Kaddish can be anything, depending upon their personal beliefs.