TV-Series
Description
Masumi Okuyama is a supporting character in Ajin. He is an Ajin, one of the immortal beings at the center of the series, who appears when Satō issues a nationwide summons for all Ajin in Japan to gather in front of the Ministry of Health, Labour and Welfare. He answers that call and becomes one of the Ajin working for Satō, serving within the group that forms around the series's central antagonist.

He was born with weak muscles in his right leg and walks with the aid of crutches. A notable detail of his condition is that, even after dying and being revived through his Ajin abilities, his leg remains weakened and does not heal. He is an adult man with a somewhat stout build, untidy stubble, and brown eyes. His blond or yellow hair is cut to ear length and appears to be dyed, as his eyebrows remain naturally black.

Okuyama is defined by his technical competence rather than by physical prowess. He is highly knowledgeable about guns and computers, making him a practically skilled member of Satō's group despite his physical limitation. His personality is conveyed mainly through his calm, workmanlike conduct as an operative, and he does not stand out as a vocal or theatrical figure compared to the more forceful members of Satō's circle.

His role in the story is that of a supporting Ajin aligned with Satō. He joins the faction after the public summons, and his practical expertise in weapons and information technology makes him useful to the group's operations. His most significant relationship is with Satō, whose authority he follows, and he also works alongside the other Ajin who answer the same call and form the core of Satō's followers.

In terms of development, the story gives relatively little attention to his personal history or an individual arc. He is introduced in connection with the gathering of Ajin and functions primarily as part of Satō's team, with his defining traits remaining his physical disability, his technical knowledge, and his loyalty to the cause.

As an Ajin, Okuyama possesses immortality and the ability to regenerate from fatal injuries. He also demonstrates strong command over his IBM, the invisible black ghost entity that Ajin can manifest. His particular IBM has a skinny appearance and obeys his orders reliably, indicating that he has good control over it, which is not universal among Ajin. Combined with his expertise in firearms and computers, this makes him a capable supporting operative.