If you reread what I wrote about Zabini's gender before, you can now understand what I meant by “the role Zabini will play”. When you are writing a powerful, evil character, there is a whole minefield of possible gender stereotypes. If the character is male, it might say, “it's natural for male people to have the power all the time”. If the character is female, it's even worse: “make sure you don't let female people have power – this is what would happen!” And if you try to escape the dilemma by making your character non-binary or gender non-conforming, you just end up with “non-binary people are evil”.

My version of Zabini is binary and cis, and all of the other characters recognize zem as zir actual gender. The only people who don't know are me (the author) and you (the reader).