Nephteros

Appearance
Nephteros has dark skin, golden eyes and long silver hair. Her face looks exactly like Nephy's, however Zagan notes that she looks totally different from the neck down when she tried to impersonate Nephy and seduce him. She has a tendency to wear revealing outfits.

Personality
Nephteros is a tsundere. She is irritable and not true to her feelings, however she becomes more open after leaving Bifrons, reconciling with Nephy and getting on friendly terms with Zagan in later volumes. She is also witty and sarcastic, which is demonstrated by her roasting Barbatos (figuratively) after he was being rude to her.

Plot
She started out as a clone made from Nephy's hair by Bifrons. She was not unique and many such clones existed before Nephteros, unbeknownst to her. She gained consciousness as a girl of about 10 years old (Nephy's age at the time of losing that strand of hair that served as material for creating Nephteros), studied sorcery and celestial mysticism under Bifrons. She was fond of her master in some way, but annoyed by his treatment, which was teasing and somewhat cruel. Bifrons also treated her as a tool for researching celestial mysticism, because only high elves could use it. She was also jealous of Nephy because Bifrons wanted to snatch Nephy and hinted at the fact that Nephy was a better elf than Nephteros (though without disclosing the fact that Nephteros was cloned).

Nephteros started out as an enemy to Nephy and Zagan -- she tried to attack Nephy, then impersonate her and seduce Zagan, though both plans failed miserably. She was then abandoned by Bifrons to be devoured by a terrifying monster, however Zagan saved her at Nephy's behest. She later returned to Bifrons' side, only to be betrayed again, when she was horrified after learning that she was but one of the many clones created by the Archdemon. Bifrons set an immortal chimera on her and made her fight for her life for about a week, running through the woods and trying to fend off that horrifying creature with no food and water. She was saved by Chastille and stayed by her side out of gratitude.

Later Bifrons tried to kidnap her by attacking Kaioneides and thus incurring Zagan's ire. Zagan destroyed his base and placed a curse on Bifrons that would kill him if he ever tried to approach Nephteros again. Zagan hypothesized that Bifrons was so desperate to get Nephteros back because he (although Bifrons' gender is never disclosed throughout the story, moreover, it is stated that even Nephteros didn't know his gender) loved her. This is later somewhat confirmed because Bifrons stated that he wants to break his curse "because an annoying maggot got close to his lovely doll", possibly meaning Richard.

Nephteros was recognised by Archdemon Orias, Nephy's Mother, as her daughter and after that started referring to Zagan as Brother and to Nephy as Sister. Henceforth she stayed on friendly terms with them and other Zagan's subordinates. She continued staying by Chastille's side and helping her out with paperwork around the church. She has a suitor, one of the Angelic Knights named Richard, though she has never shown any reciprocal affection towards him so far.