How is Louise what she is in the Red Garden OVA: Dead Girls? In the OVA sequel, we are introduced to Louise who looks exactly like Lise in the Red Garden TV series. Lise is last seen dying the Animus death of turning into ashes on Roosevelt Island, so it is generally taken that Louise is a reincarnation of Lise. Later on, Louise revealed her identity as an android. (Gasp!)



How could Lise, a human girl turned Animus infected with the cursed Doral blood, reincarnate as an android? What happened during the 300-year time span between the end of the TV series and the beginning of the OVA to have caused this inconceivable transition in Lise's identity?
The answer lies within the OVA's title, Dead Girls. The OVA is a homage to the 1992 debut novel of the same name by British science fiction author Richard Calder, which


  tell[s] the tale of a virus that turns pubescent girls into vampiric gynoid dolls called Lilim, and the doomed love affair between 15-year-old Ignatz Zwakh and a Lilim assassin called Primavera.


What's more, it appears that the TV series has also drawn inspiration from the Dead Girls novel, as the Animus-Doral feud and the conditions affecting members of the two warring clans match well with the rivalry between Cartier and Kito and the conditions affecting their dolls:


  years ago during a trade war Cartier infected Kito's fake dolls with an impotence STD and in response Kito sent her own virus to infect the genuine Cartier dolls in Paris - a virus that Morgenstern thinks responsible for the doll plague.


To answer my own question, Louise was probably born a human, but was turned into an android upon contracting a virus similar to that in the novel.