Koji Kashin

is an Inner from the organisation Kara that's in charge of the sector on the outskirts of the Land of Fire.

Personality
Koji is a enigmatic man, as well as a straightforward and no-nonsense individual. While seemingly loyal to Kara, he apparently operates under his own views as he was willing to assassinate a fellow colleague. He also appears to have an interest in Boruto Uzumaki. Self-centred as he may appear, he has consistently shown himself to be a very rational and perceptive man. He is very calculating and methodical in his approach, able to immediately determine the truth of the situation before him and likewise able to determine how things will most likely play out. He is also shown to very persuasive, able to convince the very stubborn and loyal member of Kara to follow his play. Loyal as he appears to Kara, he apparently has a treacherous side in looking for a way to defeat Jigen.

Appearance
Koji is a tall man with long white hair which he keeps in a topknot, allowing some to fall to his shoulders, along with a trimmed beard along his jawline. He also noticeably wears a mask which conceals the top-half of his face, along with the black hooded robe with maroon lining that seems standard of Kara. Red markings can be seen at the corner of his eyes, extending downward and ending at some point beneath his mask. Beneath his robes, during his meetings with Kara and Ao, he wore a long maroon coat with a row of buttons on the right side; during the meeting with Kara it was left unbuttoned, but while meeting with Ao the buttons were fastened and he wore a belt over it. Later, when confronting Team Konohamaru, he donned a shorter maroon jacket with black lining and straps with buckles, as well as a brown tactical belt and armour on his upper right leg and a pouch on his left hip.

Abilities
Koji is noted to not be an ordinary person, and regards himself as an assassin. As one of the Inners of Kara, Koji is noted to be completely monstrous in terms of power. Against Konohamaru Sarutobi, one of Konoha's top jōnin of his time, Koji bluntly considered the Konoha-nin as far too inexperienced to confront him, easily overwhelming him and would have killed him if not for Boruto's Kāma. Jigen, the leader of Kara, openly acknowledged Koji as being a very capable man.

Physical Prowess
He showed noticeable stealth skill, being able to sneak up on the experienced elder in his team unnoticed, albeit he did suggest that he was losing his edge in old age and was also able to stealthily move around Konohagakure upon infiltrating the village completely unnoticed. He is also very proficient in taijutsu, able to easily counter all of Konohamaru's melee attacks and was able to implant a toad on him without being noticed for him to use his True Flames of Samadhi on the jōnin.

Ninjutsu
Koji uses ninjutsu from Konohagakure, such as toad summoning and the Rasengan. With the former, he can perform the Summoning: Boiler Toad technique to crush a human, and using the Rasengan, he can match Konohamaru's own technique. Koji can utilise Fire Release in the form of True Fire of Samadhi, that spontaneous combust an individual, which is strong enough to overcome a target's regeneration capabilities and never extinguish. He can also use fūinjutsu to paralyse targets within his erected pillars. He is also apparently very knowledgeable of other people's techniques, as he understood the nature of the Konohagakure Sensing Barrier and likewise was able to easily bypass it without setting off an alert. He is also apparently skilled in mind-probing techniques, able to extract information from the target without their knowledge and likewise able to alter their personality. Koji also appears to be skilled in shurikenjutsu, effortlessly hitting the experienced elder man among the Inners before he could react.

Versus Momoshiki Arc
In the anime, during the days leading up to the Chūnin Exams, Koji seemingly attacked a disgruntled Katasuke Tōno in his Konohagakure lab, as part of a conspiracy with Ao to place the man under a mind-controlling genjutsu in order to extract intel for Kara. Having learned that Momoshiki Ōtsutsuki was defeated, he assumed Naruto Uzumaki was the person responsible.

Ao Arc
Upon their organisation losing their vessel, Koji discusses the matter with the other members of Kara. Immediately after their meeting, Koji approaches the elderly man of their group to assassinate, and mocks him for not noticing his presence. After impaling him with a kunai, Koji incinerates the man, before thinking about Konoha. Shortly later, he approached Ao on the Thunder Train, and instructed him to retrieve the vessel Kara lost, and provided him with the weaponry for the mission. After Ao fought Team Konohamaru during his search, Koji approached him, and questioned Ao's resolve to fight fellow shinobi again. Stating his compassion has long since gone, Koji was content with his answer and warned him about their enemy preparing an ambush for him before departing.

Having watched Boruto defeat Ao, Koji summoned a toad on top of the pair, which crushed Ao to death. Refusing to enlighten them about Kara, he paralysed the team using fūinjutsu. Overcoming the technique, Konohamaru Sarutobi faced Koji alone, during which he attempted to strike Koji with his Rasengan, prompting Koji to counter it with his own. Complementing his opponent on his skill, Koji engulfed Konohamaru in flames, which triggered Boruto's Kāma activating. Shocked to see it, Boruto subconsciously absorbed Koji's techniques. Thanking Boruto for showing him it, Koji decided to leave, before complimenting Mitsuki for stopping Sarada Uchiha from recklessly pursuing him.

Kawaki Arc
Shortly after, Koji observed Team Konohamaru making contact with Kawaki, before being joined by Delta. Realising she didn't have faith in him recovering the vessel, Delta informed him that she invited Garō to partake in the mission. When Boruto revealed his Kāma to Kawaki, Koji questioned what would happen next.

After Kawaki killed Garō and fainted from overheating, Koji convinced Delta against getting rid of the Konoha-nin and retrieve Kawaki then and there, feeling that Boruto having a Kāma merited further observation before taking action, also arguing that the crash blimp made it inevitable that the world would learn about Kara before bowing to their power. Later, Koji and Delta arrived at the main gates of Konohagakure to retrieve Kawaki. While Delta stated that it would be difficult infiltrating, Koji told her to stay put before entering the village without setting anything off and began searching for Kawaki. Once inside, Koji summoned a small toad to find Kawaki, who he eventually found taking shelter in the Seventh Hokage's home.

Deciding it was too dangerous to engage Naruto Uzumaki, Koji decided to continue observing for the time being. He watched as Boruto and Kawaki decided to spar with the intent of Boruto better understanding his Kāma, the efforts resulting in Boruto injuring his hand. The two children made the Seal of Reconciliation, and Boruto was taken aback by a vision, an event which also made him instantly heal his hand. Koji was greatly intrigued by this, wondering if it was a byproduct of the Kāma and worried if Jigen had the same ability. He then noticed Delta propelling herself through the village and to Kawaki, noting how out of control she is.

After Delta was defeated by Naruto, Koji praised Naruto's strength but noted not even he could defeat Jigen, considering the Kāma, like the one in Boruto's hand the only way to do it.

Trivia

 * Koji Kashin shares his name with a folkloric magician believed to have lived in the late Muromachi period, though his historicity is debated. He is often depicted as a white-haired, bearded, elderly man in robes, and is said to have used his illusions to deceive and defraud prominent rulers such as Oda Nobunaga.