Xil'gar Trog's Soul, from a mystery at Kharid-et digsite. In addition to having no current purpose, the wiki even stating it is "heavily implied it will be useful in the future," there's numerous citations in the game stating that having a demon bound to you by contract will aid in Necromancy.
The first mention of such dates back to a text from Melzar (Before he went mad) in 2007; also of note, this was the first time the Stone of Jas was mentioned. Even the recent Succession quest has texts depicting the use of demon souls to empower oneself through the use of Necromancy.
Interacting with the soul, we are prompted with a dialogue that states: "This will suffice for now. In time, I shall be ready to rejoin the world. I hope that when I am ready, I will have your trust...or at least we will have an ironclad contract to assuage your concerns."
Xil'gar Trog not only believes himself to be irrefutably indebted to our character, but has openly stated that he is willing to enter our service without recompense in the future, "until such time that my services are no longer required."
Honestly, at this point, if the soul *isn't* used for Necromancy, then I cannot fathom when in the world it will be used.
07-Jan-2023 19:22:34