What does "sex-neutral characters" mean?
Wren, Galvin and Lonan are all on the asexual spectrum (Wren is demisexual, Galvin is graysexual and Lonan is asexual) and all 3 of them happen to be sex-indifferent.
However, not all asexuals are like that. Some asexuals are sex favorable while other asexuals are sex repulsed. Aces have different experiences, it depends on the person.