Atsushi

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.[4] Additionally, he has a prominent black streak in his hair.

Before joining the Agency, he wears rags issued by the orphanage,[5] and after he joins the Armed Detective Agency, they issue him a white button-up with the sleeves pushed to his elbows from Doppo Kunikida,[6] a loose black tie from Akiko Yosano, black pants from Yukichi Fukuzawa,[7] black fingerless gloves from Ranpo Edogawa,[6] suspenders from Kenji Miyazawa,[7] and a long black belt from Osamu Dazai.[6]

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.[8] 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.[9]

When he morphs with Rashōmon, together with his ability Beast Beneath the Moonlight, he wears the black coat of Ryūnosuke Akutagawa, and his tiger claws become longer.[10]

Atsushi is disguised as a ship worker at the Boswellian during Ranpo's negotiation with Ōchi Fukuchi.[11]

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.[5][12][13][14][15][16] 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.[17] 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.[12]

Atsushi jumps off to save a drowning man Atsushi jumps into the river to save the drowning Dazai.

All things considered, Atsushi cares deeply for his fellow Agency members and for the well-being of civilians, especially during dire situations.[18] On various instances, Atsushi would not hesitate to help and save others, even those he has never met before. One notable example is Dazai, whom he saves from "drowning" during their first encounter, albeit with some inhibition initially.[5] During his secret entrance exam where he was faced with a simulated bomb threat, he used his own body to cover the bomb and shield the other members, also people he had never met.[19]

Atsushi saving Kyōka Atsushi saving Kyōka from the bomb explosion.

He has a strong sense of morality, which also directly stems from his upbringing. He believes his worth in life depends on his ability to protect others and has an aversion to the abuse of one's power and to preventable deaths.[13][15][20] He even tries to help even his enemies at times and would often feel sympathy for most of them, as seen through his interactions with Kyōka,[13][21] Lucy Maud Montgomery,[1] Sigma,[22] and even Fukuchi during his supposed death.[23]

Atsushi frightened at Fukuchi (manga) Atsushi's initial fright in facing Kamui by himself.

However, Atsushi still experiences paralyzing fear of fighting alone and often needs a companion to aid him in battle or at times save him in order to feel confidence.[24][25] When faced with the possibility that he alone was to fight Kamui, the primary mastermind behind the global terrorism plot, Atsushi initially felt frightened after being threatened by Kamui to cut off his head. The weight of his actions deciding the world's safety and the Agency's revival further fueled the pressure Atsushi carried, even admitting that his solitude at that time surpassed that of when he was in the orphanage.[24] Hence, after Akutagawa arrived to aid him, Atsushi felt a sense of assurance, knowing that he is not alone anymore.[25]

Atsushi grabs Akutagawa using the tiger's tail Atsushi holds his own against Akutagawa, whom he was initially told to flee from by the Agency members.

Although still struggling with his self-esteem mostly due to the words of the late orphanage director, Atsushi gradually improves his confidence and sense of self. He continues to be strengthened by several missions and the clashes against the Port Mafia,[17][13][14][26][20] the Guild,[1][20][27][8] and the Rats in the House of the Dead,[10] among others. His will hardens in these tough situations, and he becomes steadfast, reliable, and intensely caring. As Akutagawa mentioned based from their various clashes, when pushed to adverse situations, Atsushi comes back as a "more bothersome enemy".[25]