Atsushi Nakajima

Atsushi has light gray hair, pale skin, and is of average height with a slim build. He has segmental heterochromia, consisting of purple on the top half of his iris and yellow along the bottom curve of his pupil. His hair is short and swept forward in loose spikes with a lock left long on the right side of his face. This uneven style is the result of bullying he suffered at the hands of other orphans in the orphanage, and he never fixed it. Additionally, he has a prominent black streak in his hair.

After he joins the Armed Detective Agency, they issue him a white button-up with the sleeves pushed to his elbows from Doppo Kunikida, a loose black tie from Akiko Yosano, black pants from Yukichi Fukuzawa, black fingerless gloves from Ranpo Edogawa, suspenders from Kenji Miyazawa, and a long black belt from Osamu Dazai.

When he transforms into a partial tiger, his eyes become tiger-eye-like, and he develops fangs. If more drastic, his limbs turn into into a tiger's, and his tail emerges. When he finally develops considerable control over his ability, he can transform fully into a white tiger with black stripes and retains the tiger's gold eyes.

When he morphs with Akutagawa's Rashōmon, together with his ability Beast Beneath the Moonlight, he wears the black coat of Ryūnosuke Akutagawa, and his tiger claws become longer.

Atsushi's traumatic past affects much of his daily life, and he is tormented with nightmares, flashbacks, and the internal monologue of the orphanage director who abused him. He has a severely low sense of self-worth and is somewhat naïve, which causes him to initially feel helpless when confronted with dangerous situations. When paralyzed in guilt and/or fear, he has difficulty reacting or understanding what to do.

He also tends to react strongly and believe things at face value, trusting others' judgment above his own and even abandoning his own instincts. For example, when learning of the ¥7 billion bounty on his head, he became convinced that he was putting the Agency at risk. He felt intense guilt and decided to leave, believing it will keep the Agency from being targeted. All things considered, Atsushi cares deeply for his fellow Agency members and for the well-being of civilians, especially during dire situations. On various instances, Atsushi would not hesitate to help and save others, even those he has never met before.