Anime Fantasy Encyclopedia

Okinawa Locals
Kaori Kinjo
Japanese VA : Mai Kadowaki
English VA : Amber Hood
Character Description
Saya’s best friend at Koza Commerce High School. Later to be reunited with Saya. Although she does not know what Saya is, nor the burden she has to carry, Kaori knows something is up and cheers Saya on.
Prof. Hirohisa Sukegawa
Japanese VA : Tamio Sobami
English [...]

The Schiff are an unstable balance between Chevaliers & Chiroptera. They are prototypes for the Corpse Corps, pseudo-Chevalier soldiers created by a group of scientists led by Boris, under the sponsorship of Amshel Goldsmith. The Schiff differ from the Chevalier and Chiroptera in certain ways. For instance, they cannot be in sunlight without being crystallized [...]

The Goldsmiths are a branch of the Goldschmidt family. The family crest of five arrows (Cinq Fleches) and the names of the five brothers are modeled after Mayer Amschel Rothschild’s family.
Diva
Japanese VA : Akiko Yajima
English VA : Kari Wahlgren
Character Description
Saya’s younger twin sister and main antagonist; she’s the greatest sworn enemy of the Red Shield. [...]

Red Shield is a group or an organization that is solely dedicated to killing Diva and exterminating Chiropterans from the face of the Earth. Many or most of its members are actually ex-soldiers who have encountered Chiropterans out in the field and were also the sole survivors of the subsequent attack on their unit.
David
Japanese VA [...]

Saya Otonashi
Japanese VA : Eri Kitamura
English VA : Kari Wahlgren
Character Description
At the start of the series, Saya appears to be a high school girl living a normal life on the island of Okinawa. She is adopted by George Miyagusuku and has no memory of her life earlier than one year ago.
She is able to heal [...]