Advanced Ayanami Series

Advanced Ayanami Series (アドバンスド綾波シリーズ) are fictional characters from the Rebuild of Evangelion movie series.

Profile
Similar to Rei Ayanami, they have short blue hair, red eyes and female features like breasts. Like the other Rei's, they were made and are maintained by NERV for the purpose of piloting Evangelion.

Evangelion: 3.0+1.0 Thrice Upon A Time
First shown at NERV HQ, Kōzō Fuyutsuki refers to them as the resurrection of the Advanced Ayanami Series, beings that are "untainted life forms made with pure souls free of sexual distinction, which shall be the sacrificial offering to the Vessel of the Adams.".

While never shown piloting or entering into plugs, it is implied that they were made to pilot Evangelion Mark.09-A, Evangelion Mark.10, Evangelion Mark.11 and Evangelion Mark.12. These units appear during the final confrontation to open the gates of Guf and are all subsequently destroyed by Evangelion Unit-08/Unit-08γ, presumably killing each pilot in the process.

Trivia

 * While the exact details of the series being free from sexual distinction are unclear, the nature of their creation along with this description is similar to more modern interpretations of Homunculi from shows like Full Metal Alchemist and Symphogear.