Teruko appears as a short, young girl wearing the standard Hunting Dogs uniform, albeit the hat sports enough space for her hair. Her hair is light, long, styled in a wavy ponytail and tied with what appears to be a large ribbon. Befitting of the Mad Dogs, she has a sword by her side.
Teruko is intense and boastful. She revels in her power and role among the Hunting Dogs. She has a significantly short fuse and easily intimidates strangers after the initial shock of her youthful appearance disappears. She is aggressive when angered or provoked.
Her temper is so extreme that she regularly threatens violent action against people who oppose her, involving evisceration and gutting. Lower-ranked authorities refer to her as the blood-briar queen, a member infamous for her bloodthirst and feared even by her allies, she uses a steel whip as her main weapon. She also seems to have an abnormal obsession with Ōchi Fukuchi.
Befitting as the Vice-Commander of the Hunting Dogs, Teruko takes her duties very seriously even if she enjoys the experience of battle along the way, often seen laughing in joy as she takes down her opponents. She considers herself a "Protector of Justice" and gladly continues to engage in combat even when heavily injured, stating that is what heroes do. Teruko takes pride in her status as a Hunting Dog member as she described the Sigma about how a Hunting Dog is a "slave" to society and the "ultimate violence" above all that is necessary to maintain the nation and the world's order and peace and that she would gladly sacrifice her own body and soul via being required to undergo monthly maintenance surgeries and fight to the death for the sake of the people.
Gasp of the Soul (魂の喘ぎ, Tamashī no Aegi?). Teruko's ability allow's her to manipulate the age of anyone she touches. Teruko herself mainly uses her ability for interrogation and torture,with her ability allowing her to rapidly age someone to old age and cause them to develop several illnesses and maladies normal to old people,before rapidly pulling them back to a much younger age, putting a severe psychological strain on her victims senses and severely damaging them mentally due to how quickly she alters their age before they can acclimate to the new sensation and feelings of their rapidly changing bodies. Making her ability ideal for interrogations due to her not actually "hurting" her victims.
Other than this Teruko has also displayed the ability to use her ability on herself, allowing her to alter her physical age for both disguising herself and to mature her body to a more physically stronger age.
Teruko's rocket is the last to land of the Hunting Dogs, with her furious she can't get out, demanding blood and expressing her endless bloodlust. After Saigiku Jōno frees her, she claims she would have pruned everyone's limbs like bonsai trees - a hobby she partakes in.
Jōno attempts to brief her on the situation, but Teruko cuts him off, warning him not to 'read' her mood by listening to her heartbeat, as it will only anger her more, and she'll cut off his ears as punishment. Although this silences Jōno, it doesn't faze Fukuchi, who praises his squad and expects great success from them. Hearing his praise perks Teruko up, and she's more than happy to vow risking her life for him. Jōno fails to understand her erratic moods.
The Dogs discuss possible routes the Armed Detective Agency will take to try escaping the authorities. Teruko asks if there's more than two options, to which Jōno assures her there are no routes he isn't familiar with that the Agency would take. Musing which path the Agency takes, Teruko takes delight knowing that one wrong move could end in their demise, and she refers to them as "pitiful dogs", flashing a wicked smile.
Teruko instructs the group they will go both routes, tearing apart their enemy's schemes ahead of time as they always do. She and Fukuchi go the northern station route. Although the military only has one working vehicle, Teruko and the other Dogs depict superhuman speed, making a car unnecessary.
- (To Sigma) "Without order, people 'built for violence' would end up standing above the population. A world like that would be garbage. Therefore, if the Hunting Dogs exercise the strongest power as society's servants… We are searing the flames of order into our own selves."
- Her author namesake was a student of the real-life Sōseki Natsume.