Is Katasuke Tono part of Kara?

No. He is Konoha's chief scientist: a special jonin, head of the village's Scientific Ninja Tools Team. He was manipulated by Kara — placed under genjutsu by one of its agents — but never joined the organization. Not to be confused with Amado, Kara's scientist.

What is the Kote, and why did Naruto refuse it at the Chunin Exams?

The Kote is a gauntlet into which you load scroll cartridges holding sealed jutsu, released by a hand sign. The technical subtlety: the energy comes from a capacitor built into the device, so the jutsu costs the wearer no chakra. Naruto refused it at the exam because it gives an unfair advantage and ruins the purpose of the test.

Was it really Katasuke who gave the Kote to Boruto?

Yes, and that is the key point. Under genjutsu, he exploits his friendship with Boruto and the boy's desire to surpass his father to get him to test the banned gauntlet. Boruto's fault remains real, but the tool was not stolen from him: it was handed to him.

What is the connection between Katasuke and Ao?

A tragic connection in two stages. After the Fourth Great Ninja War, Katasuke fits Ao — a badly maimed former Kirigakure sensor — with rehabilitation prosthetics that give him a normal life back. Then Kara recovers Ao and militarizes those same prosthetics, without their creator's knowledge.

Is Katasuke a traitor?

No — and mind the medium. In the 2015 movie, he acts of his own free will and ends up demoted. In the manga and the anime, it is revealed later that he was under a genjutsu cast by a Kara agent: the hold is broken by Ino Yamanaka, Ibiki informs the Hokage, and Katasuke is cleared.

Katasuke Tôno : le père des outils scientifiques

Katasuke Tono: The Father of the Scientific Ninja Tools

July 27, 2026

1530 words | Reading time: 8 min

BorutoKatasukeKonoha

Prosthetics for the war's amputees, a cheating gauntlet for Boruto. Katasuke Tono, a special jonin heading Konoha's Scientific Ninja Tools Team, is the man who brought technology into the ninja world. This profile retraces the birth of the Kote, the cheating scandal that cost Boruto his disqualification, the Kara genjutsu that manipulated him, and the tragic connection with Ao, whom he had fitted with prosthetics after the war. A victim, not a traitor.

The Man Who Brought Technology Into the Ninja World — for better and for worse. Katasuke Tono gave prosthetics to the war's amputees, and a cheating gauntlet to Boruto. The profile of a manipulated scientist.

Konoha's Chief Scientist
The Kote, His Flagship Invention
The Boruto Cheating Scandal
Manipulated Under Genjutsu
The Tragic Connection With Ao
Summary Table
FAQ

Konoha's Chief Scientist

Katasuke Tono is a special jonin of Konoha, heading the village's Scientific Ninja Tools Team. He never belonged to Kara: he was its victim.

After the Fourth Great Ninja War, he first makes his name as a specialist in prosthetics, developing artificial limbs that give amputees a normal life back. His stated goal: to put ninjutsu at the service of civilians' everyday lives.

Portrait of a brown-haired man with turquoise-framed glasses, in a white lab coat over a dark turtleneck. — The man heading Konoha's Scientific Ninja Tools Team: a village engineer, never a member of Kara.

The Kote, His Flagship Invention

The Kote — the Shinobi Gauntlet — is his masterpiece: a forearm device that releases a ready-made jutsu. Katasuke did not design it as a weapon. He builds it so that anyone, even a civilian without the slightest training, can set one off. That is the goal already guiding his postwar prosthetics: to modernize ninjutsu until it serves everyone's daily life. The whole family of scientific ninja tools stems from that intention.

The gauntlet affair costs him dearly. When he forces the Kote into the Chunin Exams against the Hokage's wishes, Katasuke is in fact under a genjutsu from Kara: Naruto places him in detention, and it takes Ino searching his mind for the hold to be found and broken. Shikamaru then announces that he will get his post back at the head of the scientific team once he has recovered. The rest is personal: even manipulated, he is ashamed of having acted so recklessly, ashamed of having let his research fall into enemy hands, to the point of regretting having created it.

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Close-up of a forearm fitted with a circular metal case, while an outstretched hand presents two small colored cartridges. — The case and its cartridges: the jutsu is prepared in advance, then released with no special training.

The Boruto Cheating Scandal

The Seventh Hokage refuses the use of these tools at the Chunin Exams: the gauntlet would give an unfair advantage and ruin the purpose of the test.

Katasuke goes ahead anyway. He exploits his friendship with Boruto and the boy's desire to surpass his father to hand him a Kote — it really is he who hands it over, not Boruto who steals it. Naruto exposes the cheating and disqualifies his son.

In the Hokage's office with its large picture windows, a man in a white lab coat, seen from behind, holds out a small gray device to the blond ninja seated behind the desk, his bandaged hand resting on the desktop; on the left, a man with a spiky ponytail and a light-colored coat looks on, arms crossed. » (keep « a man »: it's Shikamaru, and remove only the forearm device) — The Seventh Hokage, here facing the inventor and his device, will refuse its use at the Chunin Exams.

Manipulated Under Genjutsu

The truth comes out later, and it changes everything: in the manga and the anime, Katasuke was acting under genjutsu, cast by a Kara agent to extract his data. Under its hold, his personality flips — arrogant, manipulative, remorseless.

The hold is broken by a mind technique from Ino Yamanaka, and Ibiki Morino reports the mind control to the Hokage. Katasuke is cleared. A nuance by medium: in the 2015 movie, there is no genjutsu — there he acts of his own free will and ends up demoted.

The face of a bespectacled man, frozen and pallid under a blue light, a dark silhouette behind him and rows of aligned eyes in the background. — The hold: the genjutsu is cast by a Kara agent who came to extract his data.

The Tragic Connection With Ao

It was Katasuke who had fitted Ao, the badly maimed former Kirigakure sensor, with rehabilitation prosthetics. Tools for healing, not weapons.

Kara then militarized them without his knowledge. Later, Ao would even steal a prototype absorption gauntlet from him to turn it against the team of Konohamaru. Never to be confused with Amado, Kara's scientist.

In a rocky gorge, a man in a long turquoise coat faces a group of Konoha ninja; a man lies on the ground on the left. — The tools designed to repair Ao end up aimed at a team from the village.

Summary Table

Aspect	Details
Identity and rank	Katasuke Tono, special jonin of Konoha, head of the Scientific Ninja Tools Team. Debut: Boruto manga ch. 1, anime ep. 43, 2015 movie.
Flagship invention	The Kote (Shinobi Gauntlet): scroll cartridges holding sealed jutsu, released with a hand sign. The energy comes from a built-in capacitor — no chakra spent by the wearer.
The Boruto affair	Under influence, he hands a Kote to Boruto and urges him to go against the Hokage's refusal. Naruto exposes the cheating and disqualifies his son.
Ao	Katasuke fits him with rehabilitation prosthetics after the war; Kara militarizes them without his knowledge. A Kara agent places Katasuke under genjutsu to steal his data.
Redemption	Manga/anime: genjutsu broken by Ino Yamanaka, mind control reported to the Hokage by Ibiki, Katasuke cleared. 2015 movie: no genjutsu, he acts alone and is demoted.

FAQ

Is Katasuke Tono part of Kara?
No. He is Konoha's chief scientist: a special jonin, head of the village's Scientific Ninja Tools Team. He was manipulated by Kara — placed under genjutsu by one of its agents — but never joined the organization. Not to be confused with Amado, Kara's scientist.
What is the Kote, and why did Naruto refuse it at the Chunin Exams?
The Kote is a gauntlet into which you load scroll cartridges holding sealed jutsu, released by a hand sign. The technical subtlety: the energy comes from a capacitor built into the device, so the jutsu costs the wearer no chakra. Naruto refused it at the exam because it gives an unfair advantage and ruins the purpose of the test.
Was it really Katasuke who gave the Kote to Boruto?
Yes, and that is the key point. Under genjutsu, he exploits his friendship with Boruto and the boy's desire to surpass his father to get him to test the banned gauntlet. Boruto's fault remains real, but the tool was not stolen from him: it was handed to him.
What is the connection between Katasuke and Ao?
A tragic connection in two stages. After the Fourth Great Ninja War, Katasuke fits Ao — a badly maimed former Kirigakure sensor — with rehabilitation prosthetics that give him a normal life back. Then Kara recovers Ao and militarizes those same prosthetics, without their creator's knowledge.
Is Katasuke a traitor?
No — and mind the medium. In the 2015 movie, he acts of his own free will and ends up demoted. In the manga and the anime, it is revealed later that he was under a genjutsu cast by a Kara agent: the hold is broken by Ino Yamanaka, Ibiki informs the Hokage, and Katasuke is cleared.

In summary

Katasuke is the scientist outrun by his own invention: he wanted to make ninjutsu accessible to everyone, and he handed Kara a key to the shinobi world. Neither traitor nor hero — a man whose enthusiasm was turned against him, and who will have to live with it.