We have all used soultrap at least once, but I was wandering what would happen to a person whose soul is needed by several magick sources. For example, useing a normal and Herma-Mora's soultrap on an assassination target of the Dark Brotherhood. Would the soul be torn into three different parts, one for you, one for Herma-Mora, and one for Sithis? Are there any other types of soultraps that may be applied?
1. Sithis is not a god. He "isn't" at all, and does not care for souls.
2. The whole soul would end up in the gem, doesn't matter if it's a "normal" one of Mora's "special" ones. In case of the gem given by HM in Oblivion, it has the capacity of storing more than one soul in it. The souls does not automatically get "sent" to him. That is why you still have to give him the gem.
What if thiis was done on a Dremora? Would part of the essence be sent to Oblivion, into your soulgem, and any other soul taking items/spells? Does any of this make sense to anyone at all?
As said, the whole sould gets stored in the soulgem. It is imprisoned there untill the gem is destroyed, or it's "charges" are fully used up by the magical item. Then the Daedra can return to Oblivion.