Lilin is first mentioned in E24 Director's Cut, as part of an exchange between Kaworu and Rei at ~18:52:
- Kaworu: You must be the first child. Am I correct? You are Rei Ayanami. And you are the same as I am. How interesting that both of us have ended up in the same form as the Lilin for life on this planet.
- Rei: Identify yourself!