How does the tree of wisdom decide which soul fragment you get?

[Strangle McDangle]

Is the type of soul fragment you get (i.e. phost) always constant for a given slot in the tree?

In my current playthrough I hardly have any Fet, and I've filled out a very large portion of the tree so far. I was under the impression that the type of soul fragment you get only depends on the slot you put the card into because it never seems to be different when I put different cards in the same slot.

But if that's the case, why am I so flush with Phost and so starved for Fet? Is it just to do with the beginning of the game choices about which elements to take?

[szbnahl]

Each skill has a fixed soul fragment for each of the wisdoms to which it can be assigned. I believe each wisdom has only 2 fragments it can produce, e.g. Skolekosophy will always provide Ereb or Shapt, but assigning Sand Stories to Skolekosophy will always provide Shapt.

If it's Fet you want, that's provided by Horomachistry and Nyctodromy, but some skills assigned to Horomachistry will instead give Mettle, while some skills assigned to Nyctodromy will instead give Shapt.

I'm not going to list every skill here, because this post is already quite long enough, but you can check the wiki[book-of-hours.fandom.com] or search the Steam discussion boards for one of the wisdom tree spreadsheets floating around.

[SCPantera]

tl;dr every skill/wisdom branch combo gives a different soul element but every skill can only be placed in two possible branches and each branch only has two possible soul elements it can give

It's sort of natural to be fairly imbalanced on soul elements in the early game, influenced mostly by your starting decisions and then secondarily by what kind of luck you have with uncatalogued book RNG.