I’m gonna go for the odd choice. Whiskey.
I liked all those other characters, and was legitimately sad when they died, but for some strange reason, I loved Whiskey best. I almost thought I would have liked to see the series from her perspective rather than Echo’s.
There was just something about her character that was never explored, and yet deeper than most everyone else. I mean, she has one of the biggest parts to play out of all the dolls (save Echo, of course) and yet we know the least about her. Her story is never told. Some girl traded her life long ago to become Whiskey. Then Alpha mutilated her, and her life is basically forfeited. She never reunites with her consciousness, and in fact (it is assumed) sacrifices herself, and dies, all alone. Never truly part of the group.