Wood

From extensive research and trials with many different materials, the people of Vaskeer have found that only one substance other than the human body actually conducts souls. This is wood. More generally, it is plantlife that absorbs souls, but it must be of quite a large size, so is often just referred to as wood from a tree since they always grow big enough. Animal souls, if they do exist which many do not believe, cannot be absorbed into wood. Or if they are, then it cannot be noticed by humans. There is a single tree which has grown large enough to hold human souls, the M’Boukho, or Spirit Tree. It towers over the land and grows supernaturally large from the souls within it. Otherwise, different plants have been found to affect souls as they are expelled from the human body, turning the soul into a natural element. This is now utilized by shamans and warlocks to cast spells.