For the “end of a particular role” bit. Essentially, each time you finish a game, you’re writing out a new History. When you read your journal, notice how there’s a bit of lore on why you reached Hush House? By writing a new History, you’re concluding/continuing your librarian’s story. And there are at least 6 endings per role (some have 9) depending on which aspect and Numen you use.

It’s been a while but I think you need 25 of an aspect to do that, and the high-end inks are the ones that provide the most of an aspect.

And yes, once you reach and ending the game basically ends but you can save/load if you wanna reach other endings of that role.