TV-Series
Description
Masami Eiri is a key figure in the story, serving as the primary antagonist. Originally a computer programmer at Tachibana General Laboratories, he was the lead designer of Protocol 7, a next-generation Internet protocol. During its development, he secretly inserted code that allowed him to control the protocol at will and embedded his own consciousness into it. This unauthorized action led to his dismissal from the company, and soon afterward his physical body was found dead on a railway in what appeared to be a suicide. In reality, he had abandoned his physical form to exist as a digital entity within the Wired, the vast global communications network.

Eiri holds a firm belief that the only way for humanity to evolve further is to shed physical limitations and live as pure digital beings. He sees the physical world as a constraint and views himself as a god of the Wired, referring to himself as such. His personality is marked by arrogance, cold calculation, and a strong desire for control. He is manipulative and coercive, using promises of transcendence and direct threats to achieve his goals. He sees Lain Iwakura as the key to merging the Wired with the physical world, and he attempts to persuade or force her to join him in that endeavor.

His role in the story is that of a catalyst and an opposing force to Lain. As a digital god, he exerts influence over the Wired and its users, and he is worshipped by the hacker group known as the Knights of the Eastern Calculus, who work to dismantle the boundary between the virtual and the real. Eiri's actions directly threaten the stability of both realms, and he is the central figure Lain must confront. In the climactic confrontation, Eiri becomes infuriated by Lain's resistance and attempts to manifest physically, taking on a grotesque, floating form with prehensile tongue and fleshy growths. Lain defeats him by telekinetically hurling her hardware and equipment at him, destroying that physical manifestation.

After Lain resets reality, erasing everyone's memory of her and restoring the separation between the Wired and the physical world, Eiri is seen in an altered timeline. In this new reality, he is alive and working as a disgruntled employee at Tachibana General Laboratories, muttering about quitting. This suggests that his digital ascension and its consequences have been undone, though the exact nature of his existence in the reset world remains ambiguous.

Eiri's notable abilities include full control over Protocol 7, which grants him near-omnipotence within the Wired. He can appear as spectral projections, manipulate digital information, and even force a physical manifestation despite having discarded his body. He is also able to communicate with and manipulate people through the network, and his embedded consciousness persists even after the death of his physical form. His key relationship is with Lain, whom he sees as both a tool and a rival. He also has an implicit connection to the Knights of the Eastern Calculus, who follow his ideology. His development is largely static; he begins as a megalomaniacal digital god and ends as a defeated figure whose plans are overturned, though his earlier hubris is never truly reformed.