Divergent discussion

I was so confused when I read about her... What's her importance?

I am confused about her too but my friends and I figured out that she might be either Tris's grandmother or great grandmother but then also come in this complication of the fact that you can either keep your last name you had before you were married or you can change it to your spouse3s last name or also you can change it to something new entirly but only in the abnegation faction.