Katasuke Tōno

is a tokubetsu jōnin from Konohagakure. He worked with Kōsuke for Konoha's Science Ninja Weapons Team.

Personality
While seemingly loyal to Konoha and working to advance its prosperity, Katasuke's main goal is his own success and status. A very arrogant, immoral and self-serving man, he takes great pride in his scientific advances. Believing strongly that his work is the new era of shinobi combat, he regularly makes video journals of his work. He is also quite stubborn and self-absorbed, to the point of defying rules and orders, as even though Naruto, the Seventh Hokage, told him that he could not use the Chūnin Exams as a chance to show off his Kote, he did so anyway. Even after Boruto's disqualification in the Chūnin Exams for using the Kote, Katasuke still tried to convince the spectators of his superior ninja tools as beneficial to the village.

He is also very reckless and over-confident, as he snuck into the battle against Momoshiki Ōtsutsuki, planning to kill the power-hungry man for further publicity of himself and of his invention, only to instead give Momoshiki extra chakra to absorb and restore his power. This move shows that for all his methodical approach to science, he is very ignorant on the battlefield, as evident by his forgetting completely about Momoshiki's ability to absorb abilities, plus not even considering the potential danger of the enemy's new form, and not listening to Naruto in the first place when he told Katasuke to not attack Momoshiki.

However, after the battle with Momoshiki, it is revealed that Katasuke's behavior was caused due to him being controlled by someone, as Shikamaru stated that Katasuke was acting weird sometime prior the Chūnin Exams, and as a result, his true personality isn't truly displayed, although after he's freed from being controlled, Katasuke becomes extremely shocked about his actions to the point where he was momentarily paralyzed after learning about it.

Appearance
Katasuke has a short crop of brown hair and brown eyes and wears a pair of glasses. In every day duties, he wears a complete white scientist suit without a forehead protector. In battle, he wears a complete standard Konohagakure jōnin uniform, however, rather than a standard red arm band depicting the Uzushiogakure crest, he wears white arm band depicting the Science Ninja Weapons Team crest.

Abilities
While his abilities are largely unknown, being a tokubetsu jōnin, it is safe to assume that Katasuke is a rather capable ninja. As a member of Konoha's Science Ninja Weapons Team and inventor of the innovative Kote, Katasuke is a highly intelligent man. He can also be manipulative as he used Boruto Uzumaki's desire to surpass his father as a way of getting the boy to use his Kote. Katasuke is also fairly stealthy, as he was able to sneak through Sasuke's temporal portal almost unnoticed.

Versus Momoshiki Arc
Katasuke invents a forearm device that stores and releases ninjutsu at the user's will. He wanted to introduce it at the Chūnin Exams but the Seventh Hokage considered it to be a form of cheating and forbade it. However, unbeknownst to Naruto, Katasuke gives the device to Boruto to use in the Chūnin Exams, in the hopes of gaining publicity for his invention. Once Naruto discovers this and disqualifies Boruto for cheating, Katasuke tries to announce to the audience that there was no point in using traditional ninjutsu techniques due to how far advanced their technology is before Momoshiki and Kinshiki Ōtsutsuki attacked the arena. Katasuke and his assistant secretly follow the rescue mission sent to rescue Naruto from the two enemies. After Naruto and Sasuke Uchiha defeated Momoshiki, Katasuke rushed in an attempt to finish off the enemy with his device and claim the credit for the victory. However, he inadvertently restored Momoshiki's strength as the latter was able to absorb the attacks Katasuke fired at him. As a result, Katasuke was stripped of his position and was forced to do menial labour to help rebuild after Momoshiki's attack.

After the battle, however, Shikamaru Nara states that Katasuke was being controlled by someone, which was the cause for his recent behavior, and stated that Katasuke was genuinely, and extremely, shocked about his actions, and Shikamaru stated that once Katasuke was fully back to normal, he would reinstate his position in the Science Ninja Weapons Team as Katasuke's brilliant mind was still very useful to Konoha.

Trivia

 * Katasuke is quite similar to Mizuki as they both tricked the sons of the Hokage into doing something risky for their own ambitions at the start of the series.