ONA
Description
Eta is the seventh member of the original Seven Shadows, an elite group within the organization Shadow Garden. She is a young elf, typically between fifteen and seventeen years of age, with long brown or purple hair and a perpetually sleepy or disinterested expression. While her standard attire consists of the black slime bodysuit and cloak worn by the organization, in her civilian life she is known as Eta Lloyd Wright, a prodigious architect whose work has received top industry awards.

Eta possesses a genius-level intellect, but it is focused almost exclusively on her personal interests, primarily scientific research and technological development. When engaged in a project that fascinates her, she displays immense dedication, often forgoing sleep for days at a time. When not interested in a subject or conversation, she becomes lethargic and is prone to falling asleep on the spot, even during important meetings. This narrow focus and her willingness to prioritize progress over safety have earned her a reputation as a classic mad scientist. Her guiding principle is that sacrifice is necessary for development, and she has no qualms about conducting dangerous experiments on her allies without their consent. Members like Beta, Delta, and Epsilon have all been unwilling test subjects for her various drugs and inventions.

Unlike almost every other member of Shadow Garden, Eta's loyalty is not primarily to the leader, Shadow, as a person. Instead, her driving motivation is an obsessive fascination with the knowledge he possesses, which she calls Shadow Wisdom. The scientific and otherworldly concepts he has shared are the foundation of nearly all her research, and her greatest joy is listening to him speak, even for an entire night. This obsession has led her to attempt various experiments on Shadow himself, including lacing his drinks with aphrodisiacs and even deadly poisons, all of which have failed due to his mysterious resilience. Despite her dangerous fixation, she acknowledges his unique existence and has stated that she would not hesitate to sacrifice her own life for his.

Her role within Shadow Garden is the head of its research and development division. She is responsible for many of the organization's technological advancements, having developed numerous types of slime suits and weapons based on Shadow's original prototype. Her inventive genius extends to the public-facing Mitsugoshi Company, where she designs buildings, creates popular products for the fashion brand Comme ça de Mitsugoshi, and has pioneered the development of internal combustion engines and automobiles after an oil field was discovered. Her ability to decode and understand languages is also exceptional; she was able to learn fluent Japanese simply by listening to a few sentences from an Earthling named Akane Nishino.

In terms of personal relationships, Eta's dynamic with the other Shades is often strained by her actions. Alpha, the group's leader, is cordial with her but remains wary of her lack of ethics. Gamma, who manages the organization's finances, dislikes how much of the budget Eta consumes with her experiments, though the resulting technologies are considered adequate compensation. Her relationships with Beta, Delta, and Epsilon are often marked by her using them as test subjects, which leads to conflict and fear, though she can also become angry if she feels they are mocking her work. She is generally disliked by newer members, such as Akane Nishino, who find her dangerous.

Eta shows very little character development over the course of the story, remaining consistently driven by her singular passion for research. Her nature is well-established from her introduction; she is a static character whose actions are always predictable in their pursuit of new knowledge and experimental data. A deeper look into her perspective is offered in the fifth volume of the light novel series, which includes a chapter presented as Eta's Research Journal.

While she is not a front-line combatant, her abilities in battle are notable. She can use her slime weapon to create a large number of swords and launch them as high-velocity projectiles for long-range attacks, a technique known as Deadly Slime Sword Rain. Despite her sleepy demeanor, when fully awake she possesses considerable physical strength, nearly on par with other powerful members like Zeta and Delta, a result of her early training under Shadow. However, her true power remains her unparalleled intellect, which makes her the most technically gifted member of Shadow Garden and the driving force behind its scientific progress.