
The Machinist's Soul Crystal, at least from what I saw from the opening quest (I haven't gone any further), is actually artificial. It was specifically created for applying your aether to your gun. Whether it carries all the same functionality or if a person was "used" as part of its creation, I don't know. That would be extremely dark though, and thus not all that likely to me.
I'll probably know more once I actually level it.
Also, you find the DRK's soul crystal on the body of a DRK that got killed by one of the Ishgardian soldiers.
I'll probably know more once I actually level it.

Also, you find the DRK's soul crystal on the body of a DRK that got killed by one of the Ishgardian soldiers.