Actually, looks like saline solution, which is basically salt water for blood infusion. Yuuka spotted it, but judging by how Akyuu stopped her from commenting further, some of the judges are aware of the kayfabe.
Eirin is a Lunarian, not an official immortal. There are no official sources that state her to be one. Drinking Hourai Elixir is a crime in and of itself on the Moon. Since Eirin is still seen with high-regard there it is unlikely she took it.
But... I thought that lunarian immortality was only limited to lifespan and that they could still be killed by normal means. Then again, most residents of Gensokyo probably wouldn't know that.
Ahahahaha!It's working all right!Kyaaaa!Thud!A drug which makes one lose their immortality!!What the!?Shfft...What am I doing?Jaakkk!WaaaahEpisode 627: Revenge of a RabbitFrom the Artist's Pixiv page.Forbidden researchAkyuu:
However, her opponent is an immortal.SalinePlease don't read it aloud, Miss Yuuka.Ah!Eirin has collapsed from the stab!What are you doing, Udonge!!?Yuuka:
What is that? Sali-...Stop it!She has collapsed!Just now, I've stabbed her...Disowned!?What is she doing here, then!?This is my revenge on you people for abandoning me!!She has stabbed her with something!Akyuu:
Just a stab is nothing to her.Ah, no!...with what she has researched!Does such a drug exist?!
