TV-Series
Description
Adam is a silver-haired humanoid machine who serves as a primary antagonist in the anime NieR:Automata Ver 1.1a. He is introduced as a mysterious figure born from a cocoon of machine lifeforms alongside his younger twin brother, Eve. Adam is the older of the two and takes on a role of guidance and authority over his sibling.

Adam possesses a cool-headed and intellectual temperament, but this calm exterior belies a capacity for relentless and merciless action in pursuit of his goals. His primary objective is the study of humanity and all concepts related to them. He has a deep, almost obsessive fascination with human nature, particularly the concept of death. To Adam, death is an extremely complex and defining characteristic of humanity, as it represents a permanent end for humans, whereas machine lifeforms can simply regenerate or reconnect to the network. This pursuit of understanding drives much of his behavior. In the light novel adaptation, his character is shown to be more complicated and depressed, revealing that he harbors a deep hatred for whoever placed him and Eve into a world without proper education or care. He also displays masochistic tendencies, as he enjoys feeling pain because it is reminiscent of human feelings.

Adam's role in the story is that of a philosophical antagonist to the YoRHa androids, specifically 2B and 9S. He is a highly advanced machine lifeform that has evolved to bear a far closer resemblance to androids than to other machines. His actions are driven by a desire to understand humanity by any means necessary. He creates the Copied City, an imitation of a human settlement, as a stage for his experiments. His motivations center on dissecting the human condition, and he eventually disconnects himself from the machine network, willingly making himself mortal in a final attempt to truly grasp the concepts of life and death by putting his own existence on the line against 2B.

The key relationship in Adam's life is with his twin brother, Eve. Adam is shown to be a good brother and a role model for Eve, taking care of him and agreeing to engage in activities that Eve enjoys, such as playing games that simulate human behavior. Adam thinks he is obligated to play the role of a brother, and while he worries that Eve's preference for physical activities over learning might mean they will not grow and adapt, he does not think his brother is stupid, merely that he prefers different things. In the anime, he is seen reading philosophy books and teaching Eve about human customs, even convincing Eve to address him more formally as "elder brother". Adam's relationship with the androids 2B and 9S is primarily adversarial. He views them as subjects for his study, particularly 9S, whom he captures and uses as bait to lure 2B into the Copied City. He taunts 2B about her emotions, trying to provoke her into expressing the hatred and anger he sees as core to humanity.

Throughout the first season of the anime, Adam undergoes a notable development from a curious observer to a desperate participant. Initially, he is content to observe humanity from a detached, academic perspective, educating himself by learning from human texts and observing android behavior. However, his fascination eventually leads him to take more direct action. He severs his connection to the machine network to experience the fear and finality of death that he believes defines human existence. His death at the hands of 2B, after Eve sacrifices himself to protect Adam, allows him to finally gain the knowledge he sought, even as he perishes.

Adam possesses a range of notable abilities that make him a formidable opponent. He is capable of telekinesis, allowing him to manipulate objects and generate pillars of light as attacks. He can also teleport, make himself intangible, and manipulate gravity. His connection to the machine network initially grants him a form of immortality, as he can regenerate from damage, but he voluntarily gives this up. He is also capable of reactive evolution, learning and acquiring new combat skills rapidly during battle. Furthermore, he created the Copied City, demonstrating his ability to manipulate matter on a large scale.