Was it planned in the first place or did you just conveniently make Cassandra an orphan that was adopted by the captain of the guard so that she could relate to Eugene?
I don’t work on the series. I didn’t plan anything.
However, at the D23 Expo panel, @cnotes said that Cassandra is the only character who’s a bit of a mystery. They don’t know 100% where she’s going. I don’t know if that means that they did not originally plan for her to be an orphan, or if that’s something that just developed about her, but it was revealed so early in the series that I wouldn’t be surprised if they always wanted it that way.