Zeta

Zeta (ゼータ) (Ζήτα) is the sixth member of Shadow Garden, being one of the original "Seven Shadows". She usually explore the world by travels alone and gathering intelligence by conducting reconnaissance. Also, unbeknownst to her fellow Shadows, she formed a sub-faction within the organization that is loyal solely to her.

Appearance
Zeta is a female Beastkin from the Golden Panther clan, having blonde hair, large cat ears, purple eyes, and a long tail. She wears the customary slime bodysuit with a large cape and an area exposing her cleavage.

Personality
Despite being a Beastkin, who are mostly known for being wild brutes, Zeta is smart and level-headed. She's shown to be a loner, usually doing her missions on her own and only cooperating on a team if the situation demands it.

From the anime's depiction of her, Zeta appears to be a tomboy who likes fighting, similar to her fellow Beastkin Delta, yet she seems to have a greater degree of self-control compared to the "loose cannon".

Compared to the rest of the Seven Shadows, Zeta is the most extreme in terms of her actions and goals. She can be so determined to achieve her mission that she would allow mass casualties to occur. Like her fellow Beastkin, she also dislikes undergarments as she finds that they restrict her movement and thus does not wear them.

Background
Zeta was originally known by the name of Lilim, and had a loving family with her father, mother and little brother. She was the daughter of the leader of the Golden Panther tribe, who were the tallest among the Beastkin tribes, who was far away from the Midgar Kingdom. Her father had been covertly investigating the "Demon Possession" since he feared that Lilim contracted it, having speculated and becoming suspicious of the beliefs of the church. Since she was little, Lilim had great intelligence and a taste for reading freely, having spent all her time investing in her focused subject.

At the same time, being the chief's daughter, she was allowed freedom from marital commitments with other Beastkin tribes. When Lilim turned twelve years old, she began showing symptoms of the Curse until they became visible and unbearable. When she told her parents, her father chose to hide the disease instead of killing her, and both would undertake a trip to the Midgar kingdom in search of a cure, according to an elf that she read about in a book. If he confirmed a cure, he would return to take Lilim as her father believed that there was someone in Midgar capable of curing the curse she had. Lilim did not believe it at all in the beginning and she was ready to be killed before her curse worsened, but she tearfully chose to trust her father and wait a month for him to return.

A month later, Lilim is still locked up in her house while she waited for her father, but those of her tribe found out through a priest of the church, really a member of the cult, that their boss had a possessed daughter of hers locked up in her house. They tied him up and killed him, but before her father tried to tell the "truth" of the Three Heroes and demon Diablos story, but no one believed him, so her father ordered his wife bring Lilim and her brother to take care of themselves and to reach the kingdom of Midgar, since there was "someone" there he believed could cure her of her Curse. Lilim fled in tears from her native tribe together with her mother, before being apprehended with her brother while she saw her father engaged against the priest and the branch family leader.

During her journey to the kingdom of Midgar, Lilim separated from her mother, who entrusted her with the care of her little brother. In regards to her curse, she was found by the village priest before her and showed her the severed head of her parents. When the priest introduces himself as Petos, Lilim finally confesses that she is the possessed in an attempt to save her little brother, but in the end Petos ends up killing him in front of her and tells her that his job will turn him into Rounds before showing her all the severed heads of the Golden Panther tribe, including the head of the branch family. Lilim enraged and strike Petos, but he make her unconscious also ordering his men to arrest the girl and take her to the laboratory of Valliora, while he prepares the preparations to be part of the faction.

When Lilim wakes up, she is furious that her entire family and tribe were killed and she loudly pleads for someone to save her and give her power. Fittingly, she was rescued by Shadow under the company of Alpha who was a little behind him, Shadow gave Lilim his power and curing her curse, while he finished off her captors. Lilim realized that everything her parents said was true, to which Shadow is surprised (since he didn't expect the invention to spread without knowing it was true) and tells him that the priest and the people who capture her were not from the Holy Church. Those men were actually from the Cult of Diabolos and they hid the truth about the Three Heroes and the story of the demon curse in the darkness of history because they wanted to bury the truth about the hero lineage that was an obstacle to them by naming the demonic curse as a "Demon Possession", also tells Lilim that they tried to revive the demon Diabolos and that they need the blood of the possessed, that is, of the girls descended from the Three Heroes. Lilim then joined Shadow Garden and under Alpha's explanations, she was given the new name that is Zeta, becoming the sixth member of the "Seven Shadows" under her master, Shadow.

First Assault on the Cult
During the case of when her lord Cid's sister, Claire Kagenou, was abducted by Viscount Grease of the Order of Diabolos, Zeta participated in the assault on the hidden secret base where Claire was kidnapped. Alongside her lord and the others of the Seven Shadows, they managed to rescue Claire after they eliminated all guards and the leader of this branch base.

Powers & Abilities
Zeta is the third-weakest member of the "Seven Shadows", with only Gamma and Eta being lower. However, whereas those two are practically useless in combat, she is still far more powerful than an average member of Shadow Garden.

Physical Prowess
It is speculated that Zeta possesses less strength compared to the "berserker" Delta, but in turn has more self-control. She specializes in reconnaissance and tracking between the "Seven Shadows" and the other Beastkin.

Cid Kagenou / Shadow
After Cid restored her to her true self, Zeta saw him as living proof that she and her father were right that there was someone that can cure Demonic Possession thus she swore absolute loyalty to him.

Zeta desired to awaken the demon Diabolos in order to obtain eternal life for Cid, ensuring that he would be the one to rule over the world.

Alpha
Being a lone wolf, Zeta mostly does her own thing without regularly reporting to Alpha, much to the latter's annoyance. She is even willing to go behind her back and supersede her authority by creating her own branch within Shadow Garden that is loyal solely to her. Unlike Delta though, Zeta remains partially at Alpha's command and doesn't dare directly challenge her unlike Delta once did.

Delta
Delta and Zeta do not get along well and constantly bicker with each other. This seems to mostly stem from their animal instincts, as Zeta is a Cat Beastkin and Delta is a Beastkin Wolf, causing them to refer to each other by the mocking names of "Cat" and "Doggie" respectively.

Nina
A member of Zeta's secret faction. After Claire began displaying symptoms of having become Diabolos' host, Zeta had Nina infiltrate Midgar Royal Spellsword Academy to watch her.

Claire Kagenō
As Shadow's older sister, Zeta cares enough about Claire to have Nina infiltrate Midgar Royal Spellsword Academy to watch over her after she began displaying symptoms of having become Diabolos' host.

Trivia

 * Due to being absent most of the time, it is still unclear if Zeta is aware that both Alpha and Epsilon are now capable of healing the possession.
 * Zeta's design was revealed first in the anime, since she has not yet had a major role in any story arc.
 * The game "The Eminence in Shadow: Master of Garden" reveals more of her character and her relations within the group, as well her role. She was responsible for Investigation of the Cult Hideout, while also searching for a new main base for Shadow Garden.