The concept behind the story is simple: What are the backstories of the various Haibane? Before We Had Wings goes with the interpretation that the Haibane are all deceased people. As a result, the story explains their deaths.
Before We Had Wings provides examples of:
- Death of a Child: The Haibane are all deceased children. The fic shows how several of them died.
- Driven to Suicide:
- Rakka jumped off of her balcony because she felt she had no place in the world.
- A depressed Reki killed herself by laying on train tracks.
- Look Both Ways: Hikari died after a hit-and-run when she was crossing the road without looking.
- Parental Neglect: Rakka mentions that her mother doesn't care about her anymore.
- Self-Harm: It's mentioned off-hand that Rakka cuts herself. Her parents don't understand why she does it.
- Sweet Tooth: Used darkly with Shota. He is a terminally ill child who loves shortcake. His mother makes it for him every day and handfeeds it to him after he grows too weak to feed himself.
- Troubling Unchildlike Behavior: Reki's age isn't mentioned but it is stated that she's too young to be smoking as much as she does.