Anastasia, in concept, is very difficult to explain, but in simple terms, she seems almost emotionless. Her backstory. I can't reveal it because it is important towards the end of Part 2, but she had a very rough childhood, and comes off as emotionless and hateful, but somehow, through that, feels nurturing. (A very monotone voice is important.) (The most important part of her voice is knocking out the emotionless vibe, while also not making her boring; it's a very difficult voice and hard to explain.)