Juliette and James

Juliette and James are Green Vampires. They are married.

Personality
James hasn't really had enough screen time...

Juliette is very determined and revenge-minded.

Story (spoiler warning)
James was assigned to kill Ronja but she took his life first.

Juliette was sent later, to try and get her to join the Green Vampires but she instead attempted to kill her to get revenge for James. She attempted on Ronja's life several times, the second time she tried to take advantage of Ronja's memory loss, and the third time she kidnapped Mike, tortured him and offered Ronja to give her life instead of his. She was eventually killed by Saia.