So, in my re-reading of Arcanum Unbounded I came to one of my favourite shorts, Mistborn: Secret History. At the portion where Kelsier meets with Khriss and Nazh I couldn't help but notice something Nazh said that I hadn't picked up on before.
This caught me and I started thinking, is it possible for one to ritualistically become a shade using whatever magic may be present on Threnody? Generally shades come about due to some weirdness in Threnody's investiture (maybe cos of large chunks of Ambition being ripped off in this system) but if one were to purposely create a shade, would it be a more powerful kind or simply like all other shades. One possibility that came to mind could be that this is how the one-time mentioned Deepest Ones come to be.
What do you all think? Is there some other info floating around out there about Threnodite shades and The Deepest Ones, could someone like Kelsier be analogous to The Deepest Ones? This is my first theory so apologies if this has been spoken about before, I look forward to hearing all your opinions on the subject, Threnody is super mysterious and so much fun to think about.