Nenki's hair is a tangled, black mess which reaches just past his waist, though can be extended to be longer than his body. His entire body, except for his hands and face, are completely covered in fur. He has pointy ears and sharp teeth, giving him a rather canine appearance. He has exceptionally large eyebrows and a lot of nose hair protruding from his nose. He wears a light grey kosode with darker grey hakama. He's best friends with Hotarubi.
Before the WarEdit
When Oboro was a child she briefly mentioned that Nenki would use his hair to bounce her up and down. In the same anime only flashback Nenki and Rousai are seen when Oboro had hiccups. As she wanders through Iga, worrying about her upcoming meeting with Gennosuke, Nenki and Rousai juump out from behind a wall and scream at her. Despite giving her a fright they are unable to cure her of her hiccups.
In another flashback he is seen with the rest of the Iga clan huddled in a group talking. They hear a noise from the room next door so they slide it open slightly and peer inside. The group catches sight of Ogen fixing her make-up and is so shocked they fall forward into Ogen's room, breaking the doors in the process.
Battle with ShougenEdit
Nenki first appears with several other Iga ninja to escort Oboro back to Iga after she spent the day with Gennosuke Kouga. They are interrupted by the sudden appearance of Jousuke Udono, followed swiftly by Rousai. Rousai accuses Jousuke of stealing a scroll belonging to Iga whick Gennosuke forces Jousuke to return. After Oboro, Gennosuke and Jousuke leave earshot the group open the scroll and read of the peace treaty being abolished. Despite the initial shock the group begins to laugh and decides to trap Gennosuke and Jousuke in Iga. Nenki suggests Oboro should take Gennosuke to Iga while Akeginu convinces Jousuke to go too. Nenki then heads to find Tenzen on Jingorou's orders.
When shown the scroll Tenzen immediately realises Shougen has the other scroll and Nenki enthusuastically proposes the group kill him. Tenzen agrees and, after sending Jingorou back to Iga, the group sets off. Not long after departing the group comes across a Kouga carrier and decide to see who's inside. After killing the guards and opening the carrier the group are confronted by Juubei Jimushi. Tenzen decides he can kill Juubei alone and sends the rest to kill Shougen.
Later that night the group finds Shougen and wastes no time in surrounding him. Nenki outright tells Shougen they are there for the scroll before leading the charge towards him. However, Shougen manages to trap Nenki, Rousai and Koshirou in a web, leaving them vulnerable. Shougen begins to taunt the ninja but is interrupted by the multitude of butterflies summoned by Hotarubi. In the confusion Nenki shouts for Hotarubi to throw him Koshirou's sickle, which he grabs with his hair and stabs into Shougen's head. As Shougen falls he throws the scroll into the bushes, which is caught by Juubei. Nenki, Rousai and Koshirou then chase after the scroll.
The three keep chasing Juubei but are unable to catch up. Tenzen then appears before Juubei and easily cuts him in half before retrieving the scroll. The group then decides to burn the other scroll after scoring off Shougen and Juubei's names.
Attack on the KougaEdit
The next day Nenki and the others decide to head to the Kouga Manjidani village and try to assassinate some of the Kouga ninjas listed on the scroll. When they enter the village Nenki takes no that they seem to have entered unnoticed. Just then Koshirou then senses someone nearby and Rousai is suddenly pulled towards the wall and held against it, while Nenki demands to know what Rousai is doing. Rousai struggles to get free and when he does he smashes the wall with a kick. Rousai informs the others the wall spoke to him just before it shouts for reinforcements. Tenzen tries to claim they were sent by Gennosuke but the ninjas know they are lying and the group are forced to attack. Nenki uses his hair to strangle the ninjas who attack him, as well as using it to throw the swords of the dead ninjas. He is also seen fighting with his bo staff. The group then approach Hyouma, Saemon, Kagerou and Gyoubu, who had emerged from the wall. Tenzen warns them not to try and get revenge as they will kill Gennosuke if they do. The group then disappears in the butterflies that Hotarubi summoned.
Return to IgaEdit
The group then begins to return to Iga with Nenki suggesting they kill Gennosuke when they return but suddenly Tenzen stops, ordering the others to hide. The group hides in the bushes and watches as Okoi appears. They waste no time in surrounding her and trying to convince her to go with them to Iga. She denies their request and leaps into the trees to head back to the Kouga village. Nenki gives chase, catapulting himself into the trees with his staff and following her by swinging on branches with his hair. She throws several kunai at him and believes she has beat him, but instead he catches them in his hair before throwing his staff forcefully into her stomach. As she falls from the tree he throws the kunai back at her but misses and she lands unconscious on the ground. Tenzen orders nenki not to kill her as he wants to interrogate her, which annoys Nenki but he agrees to bring her back to Iga.
When they reach Iga Nenki locks Okoi in the salt store before joining the meeting between Tenzen, Rousai, Akeginu and Jingorou. Akeginu fills them in on the death of Jousuke and the group decides not to tell Oboro about the scroll. Later Nenki goes to the salt shed to find Rousai and bring the scroll to Tenzen. As he enters he is attacked by Okoi, who cuts his staff in half with her knife. Nenki manages to disarm her and grapple her from behind, preventing her from moving. He grabs her breast but when he does she starts to drain the blood from his hand. She attempts to touch more skin to absorb more blood but he impales her on needles made from his hair before she can, fatally wounding her.
Not long later Yashamaru and Hotarubi enter to find Nenki without clothes on and sitting next to Okoi's body. He asks Yashamaru when he got back before talking with Hotarubi. He then tells Yashamaru that Gennosuke is still alive, accusing Tenzen of being to scared to kill him. Jingorou then shows up begging for water. Nenki leaves to throw him in the lake but when he returns he finds Hotarubi looking at the body of Rousai. When Yashamaru is revealed to be Saemon seconds later, Nenki is angered and prepares to fight him but has salt thrown in his eye. In the confusion he tangles Hotarubi in his hair. When he recovers he chases after Gyoubu, who has the scroll, with Tenzen, Hotarubi, Jingorou and some other Iga ninjas. They lose Gyoubu so head to Gennosuke's room, where they find Gennosuke reading the scroll surrounded bu Gyoubu and Saemon. Nenki goes to attack but is stopped by Tenzen, which saves his life as Gennosuke kills the other ninjas with his ninja skill. Nenki is too shocked to attempt to attack again and allows Gennosuke to walk away, injuring Koshirou in the process.
Later the remaining Iga ninjas gather and learn from Akeginu that Koshirou will live but is now blind. Tenzen blames Oboro for the incident and informs the group that Iga has likely already lost Ogen, Yashamaru and Rousai. Nenki points out the Kouga will continue to make their life hell, despite surviving their first attack. Oboro then puts something on her eyes and when Nenki asks what it was she explains it will seal her eyes shut for a week. A messenger then arrives, bringing them the scroll Gennosuke left them, leaving nenki to question Gennosuke's motives. With the scroll is a letter which informs the ninja that Gennosuke is going to Sunpu. Tenzen decides to give chase and orders Nenki and Hotarubi to go on ahead and find the Kouga then report back, warning them not to act rashly.
Assassination on GennosukeEdit
Nenki and Hotarubi run through the pouring rain after Gennosuke and the other Kouga, with Nenki annoyed at being belittled by Tenzen. He and Hotarubi then scout out Gennosuke's room froma roof before sending Hotarubi's snake to seal Gennosuke's eyes. When Gennosuke's eyes are sealed Nenki laughs, finding it too easy. However he wonders why Gyoubu is nowhere in sight. He then sends Hotarubi back to Iga to warn the others of Gyoubu, telling her he'll take care of the rest. He believes its his only way to regain his pride, damaged by Tenzen. He tells Hotarubi to lure the enemy away using her butterflies as she leaves, allowing him a chance at Gennosuke.
Nenki enters Gennosuke's room after Saemon and Kagerou were lured away, leaving only Gennosuke and Hyouma. He laughs and taunts them, making fun of their lack of sight. Nenki asks who he should kill first and laughs when gennosuke asks Hyouma to help him see. He calls Gennosuke an idiot, reminding him that Hyouma is blind. When Hyouma opens his eyes he uses the same technique Gennosuke used, forcing nenki to attack himself. His hair wraps around him, breaking all his bones and contorting him into unnatural positions. Nenki's misshapen body is left hanging by his hair from the door, with his last thoughts being how embarrassing the situation is.
Nenki is very self-confident and has no problem directly challenging another ninja to a fight. He seems to enjoy battle and takes pleasure in killing his opponents. He also seems to take every opportunity to show off his skills, shown when he immediately volunteers to kill Shougen and later to track down Okoi. He also seems slightly perverted, licking his lips when he first catches sight of Okoi and stripping her when he ties her up. His pride is important to him and he even takes the mission to kill Gennosuke to regain some of his pride he feels he has lost.
Hair Manipulation: Nenki has complete control over every hair on his body, even his nose hair. He uses his hair to grab opponents and strangle them, grab thrown weapons, swing from trees, and the hair on his body can be stiffened into needles to skewer opponents.
Bojutsu: Nenki uses a bo staff when in battle and is shown to be very proficient with it. He can throw it with enough force to cover large distances and can knock opponents out with one throw. However, he seems to favour using his hair during battle.
While he follows Tenzen's orders over those of Princess Oboro, Nenki considers Tenzen to be overly-cautious and deeply resents being held back from any fight he feels certain he can win. As a result, he frequently goes against Tenzen's orders with the intention of proving him wrong regardless of any potential risks.
Nenki is comparatively more patient with Oboro's indecission than the other Iga; viewing her infatuation with Gennosuke as a childish phase born out of her sheltered view of the world and believes that as time goes by she'll eventually grow out of it.
Nenki seems to be rather intimidated by Hotarubi, describing her as "scary". When he makes a joke about her he immediately apologises after seeing her glaring at him. He also seems to have faith in her abilities, leaving her to take care of Saemon and Kagerou.
Appearance in Other MediaEditNenki Mino was present in the 2005 live action movie Shinobi: Heart Under Blade portrayed by Shun Ito, but was significantly altered. Instead of his signature staff and hair manipulation, he was featured with a fur skin hood and cloak, long extendable iron claws, and growled instead of actually speaking; giving him a feral appearance that was highly reminiscent of Wolverine. His role in the movie was rather small and was killed not long after his introduction, making him the first of the ten selected ninja of Kouga and Iga to die. He was killed by Kagerou, whom he kissed after being seduced by her.
- Instead of having a staff like the anime or manga, the novel states that he uses a club. His appearances and abilities however, remained the same.
- The fight in the Kouga Manjidani is much shorter in the manga, where Nenki is not shown using his hair to attack at all.