Jōno is a young man with mostly light-colored hair with tips that fade into red. As he is blind, he almost always keeps his eyes closed. Along his Hunting Dogs uniform, he wears a long earring on his right ear.
Upon first appearance, Jōno has the calmest, most composed personality of the Hunting Dogs unit. However, he does not take interruptions nor injustice lightly. As such, he nonchalantly arrests Osamu Dazai upon their first meeting, expressing his thoughts against Dazai's blood-covered past with great disapproval.
Jōno hides a fierce temper behind composed expressions, mixing them with harsh threats and remarks towards his comrades. Tetchō Suehiro finds himself on the receiving end of much of these remarks due to his offbeat nature, easily exasperating Jōno. He even subtly scolds his commander Ōchi Fukuchi for the latter's theatrics towards military troops and afterwards threatens to shoot him from behind, showing that his violent tendencies are no different from his comrades. He also tends to either silently or vocally wish ill will towards other people with a rather antagonistic attitude towards him, including Tetchō and even a government official. Sensitive to his surroundings, Jōno also detests intense emotions and abrupt changes in moods from those around him.
Quite contrary to Tetchō's nature during interrogations, Jōno has a sadistic side to him in extracting information from his targets. As noted by Tetchō, he has an infamous habit of tormenting others until they are forced to spill his needed details during investigations, which he seems to find amusement in. Hence, with such a sharp persistence in information extraction, Jōno believes that he must be the "strongest Hunting Dog" among the team for his expertise in investigating and capturing criminals.
Jōno's ability, Priceless Tears (千金の涙, Senkin no Namida?) gives him incredible hearing. He is able to hear the breath and heartbeats of others without standing near them, and he is able to determine his surroundings with his hearing.
To compensate for his blindness and in addition to his ability, Jōno claims his other senses, including his smell and hearing, are incredibly strong. As such, illusions have no effect on him, which makes him immune to Jun'ichirō Tanizaki's illusions. He is also adept and invaluable during investigations, most especially in extracting information and secrets from fugitives and other targets, a skill which he combines with his ability for efficient and speedy results.
Jōno appears at the horse race Dazai attends. At first, he calmly asks Dazai which horse is winning, to which Dazai happily answers. Quick to change gears, Jōno handcuffs and arrests him for the former Port Mafia executive's crimes.
After the Decay of Angels frames the Armed Detective Agency for the political hostage situation and Nikolai Gogol's alleged murder, the Hunting Dogs are summoned by the government to aid in chasing down the runaway Agency members. Upon landing from his capsule, Jōno disrupts a military man's attempt to shoot Fukuchi by catching a bullet without fail. He subtly scolds his commander for raising the troop's heartbeats for no reason, then he threatens to shoot him from behind.
As Tetchō arrives, Jōno takes a harsh approach from the get-go, telling him to leave as soon as he came. He is quick to change gears when the vice-commander lands, worried about her anger extending to all of them. Jōno tries briefing her on the situation, only to be told to shut up, to which Jōno obliges. When Teruko starts acting cheerful around Fukuchi only, Jōno is distraught at how he cannot read her emotions whatsoever.
Elaborating their plan of attack against the Armed Detective Agency, Jōno lists the two possible routes the Agency will take: a southern highway, where the Agency could hijack a getaway car; and a northern train station, where they could blend in among the passengers. Teruko asks him if there are any possibilities, but Jōno points out he knows everything about the area, so there is no way they could take a route he does not know. He admits the southern route would be the most logical outcome, which is why he hypothesises that they shall take the northern station to throw the Hunting Dogs off.
- The military dubs Jōno the "King of Avidyā" (無明の王, Mumyō no Ō?). Ironically, avidyā is a Buddhist concept about ignorance and misconceptions, something that Jōno – with his keen senses – never risks, making him essential for interrogations.