The Hourai Elixir was created by Eirin Yagokoro using Kaguya Houraisan's power over eternity. Anyone who drinks this forbidden elixir will cease to age, never become ill, and will never be able to die. One will be as frail and vulnerable as before, but every injury shall cease; critical injuries will be healed in a matter of days. Complete destruction results in complete restoration.

The Hourai Elixir is permanent. According to Mokou, the first taste of the medicine makes the drinker incapable of growing up or aging. The second taste makes them incapable of becoming ill. The third taste makes one completely immortal to the truest sense. The ingredients of the Hourai Elixir are known only by Eirin Yagokoro, whose name points her out to be the "Mind of God", an omniscient being. Because she made the Hourai Elixir the true elixir of immortality, she probably also made it irreversible, making its effects perfectly permanent. In her confrontation with Mokou, Alice points out that the soul is made invincible. This, along with Yuyuko's and Yukari's scenario in Imperishable Night, makes it seem that the Hourai Elixir itself isn't a power that keeps one immortal, but makes one an existence completely independent of even the concept of reality, thus making one not subject to the bounds of life, death, or even manipulation, although the pain of injuries can still be felt. This medicine indeed makes one truly invincible, and forced to live out their existence forever. It's no wonder why this medicine is forbidden even to the mysterious Lunarians.

Reportedly, the ingredients of the elixir remain in the liver of whoever drinks it. Eating the raw liver of an immortal is said to grant the same immortality as drinking the elixir, though it will not deprive one from their own because they have already been rendered deathless.

The spell Flower Blossom cast may or may not be related to the Elixir.

Known Hourai Immortals: Edit

  • Kaguya Houraisan
  • Eirin Yagokoro
  • Fujiwara no Mokou
  • Flower Blossom