Advena Avis

The Advenna Avis
The Advenna Avis was a ship that sailed in 1711, carrying a crew of 30 alchemists including Maiza Avaro, Gretto Avaro, Sylvie Lumiere, Szilard Quates, Huey Laforet, Elmer Albatross, Beg Garotto, Nile, Victor Talbot, Czeslaw Meyer, and Lebreau Fermet Viralesque.

Aboard the ship, the alchemists' goal is to summon a demon in the hopes of discovering the secret of immortality, and become immortal themselves. The entire crew successfully realize their goal after the Demon is summoned and gives the entire crew some Grand Panacea, and are henceforth regarded as the original immortals. Sylvie Lumiere is the only crew member who does not immediately drink the elixir, although she does become immortal at a later time and thus is still regarded as one of the original immortals.

The Summoning Ritual
The leader of the alchemists, Maiza Avaro, is the one who initiates the summoning ritual. Standing on a spell circle carved on the deck of the Advenna Avis with Gretto and Denkuro Togo, Maiza recites the following incantation:

"I summon thee here to this place. Thou art my heaven's Earth, the night of day. Thou art the darkness of light, the goodness of the wicked. Thou art the one who sees, and the one who is seen. Thou art the creator of all destruction, the lover of all men who thou dost despise."

There seems to be more to the incantation, but is interrupted by the Demon himself, saying that their words are useless, especially "the ones in their heads", suggesting that the Demon can read minds. This suggests that parts of the ritual, or even the entire ritual itself, are necessary to summon the Demon. The summoned creature further explains that the simple thought of his being in their minds was enough to summon him.

"The words you use to summon me are nothing more than tedious trinkets. I hear your words constantly, especially those you speak inside your head. The simple thought of my being brings me instantly into your midst."

Maiza is given a bowl full of Grand Panacea and is told to drink it. Szilard Quates is the first to drink from it and is initially doubtful that it works, but is soon convinced he is immortal when the Demon kills him by slashing off his head, and comes back to life moments after.

Post-Immortality
Immediately after the crew becomes immortal, the Demon imparts with several vital pieces of information concerning immortality: The Demon also reveals that he had given the formula of the Grand Panacea. Later, the crew decides that they must keep their immortality and their abilities for themselves, and that Maiza should be the only one who knows the formula. However, Maiza later turns on his decision to keep the formula to himself and gives half of it to his brother Gretto, who initially did not want the burden but ultimately accepts it.
 * By placing their right hand on a person's head and not thinking anything, an immortal can give knowledge and memories to the person.
 * By placing their right hand on a person's head and think "I wish to eat", an immortal can devour the person and absorb all their knowledge and experiences.
 * The only way an immortal can die is by having another immortal devour them with their right hand.
 * Immortals must use their real names when conversing with other immortals. Supposedly, any immortal who uses a fake name when talking with another immortal will forget their name forever. However immortals seem to be unable to lie about their identity to another immortal, such as when Czeslaw Meyer is unable to lie about his real name when talking to Isaac and Miria on the Flying Pussyfoot, unaware that they were immortal.

Szilard Quates is the only alchemist who disagrees with the crew's decision, and is determined to obtain the formula at any cost. Later, he devours a total of thirteen immortals, including Gretto, thus receiving half of the formula. He nearly devours Maiza as well but is knocked overboard. The remaining 16 immortals, knowing Szilard will eventually return and the danger he poses to them, scatter throughout the world.