So if i am playing my second character's story and i write over the bookmark of the first one does that erase that characters story i am just a little confused by the system and with only 6 bookmarks how would it work with 13 characters

@Adam914: If you write over one character's bookmark in another's place, the previous character will be replaced. There are 6 slots total, so you need to save in different places instead of the same one. You'll have to complete your chosen 6 first (Labrys should be one of them because she's important to fully completing them!), then move on to the others that you didn't complete yet.

It's worth mentioning you can easily quick skip text you already read, even if you didn't save a bookmark. I'd recommend playing through one character at a time, though.

as long as you get to the part where it says "To Be Continued" saving over a bookmark will not erase what you've done. when you pick up the next part of a character's story you can choose to start from the beginning or the cliffhanger.