Name and age?
Where are they from?
How do they earn a living?
What should they look like?
Nothing of this is final and the characters change as the story gets fleshed out for example:
Dr. Wallstonecraft was originally and old father figure yet he evolved into a younger version to better suit the story. This being a game the story itself isn't set in stone since things need to serve a purpose and users need certain level of control as to how and when events take place.