Basilisk.

Azuki Rosai (小豆 蠟斎, Azuki Rōsai) is the oldest member of the Iga clan's top ten shinobi, not counting Tenzen. Rosai is relatively short in stature and has a large head. Despite his age, Rosai is a strong shinobi, and can break a tree with just one blow. His special technique relies on the ability to extend his limbs, allowing him to strike enemies from long distances.

Yashamaru is a member of the Iga clan (夜叉丸), a cocky and arrogant fellow whose main weapon is multiple choking threads that he uses to attack his opponents. These threads are called Kokujo (black rope), and are made from the hair of young girls and then dipped in special oils, making them as strong as steel. Yashamaru has control over the threads and can manipulate them at will: he can strangle them, cut them, or use them as needles. The threads are located mainly on Yashamaru's arms, but he also has some on his legs for emergencies. Yashamaru also has a large knife, but he rarely uses it, as his opponents usually die before they can get close to him.

Hotarubi is a member of the Iga clan (蛍火), a small and slender young woman with straight black hair that falls to her shoulders. Although Hotarubi shares her clan's hatred for the Koga, her main goal in the war is to avenge her lover, Yashamaru. She loves him so much that even the thought of him being harmed drives her into a rage. After learning of Yashamaru's death, she devotes herself entirely to the war so that she can avenge her lover's death whenever the opportunity arises. In battle, Hotarubi summons flocks of butterflies, which she can use to confuse her opponents and deliver a fatal blow where the enemy least expects it, or to escape unnoticed. She has a tamed snake that she uses as a bodyguard. Hotarubi is also an expert in tanto.

Mino Nenki is a member of the Iga clan (蓑念鬼) - his monkey-like appearance, excessive body hair, and use of a bo in combat strongly resemble Nenki's resemblance to Sun Wukong, the monkey king in Chinese mythology. Nenki is overly proud and arrogant, which leads to him underestimating his opponent. His main weapon is his own hair: he can control it and shape it into any shape he wants. His hair is strong enough to carry his own body (in the case of Oka's pursuit) and lift his opponents. Under his clothes, his body is also covered in hair, which can take the form of needles in order to attack an opponent who gets too close.

Amayo Jingoro is a member of the Iga clan (雨夜 陣五郎, Amayo Jingoro) and is one of the few in the Iga who prefer to win a fight with cunning rather than strength. By covering his body in salt, Jingoro turns into a kind of slug, which allows him to penetrate even the smallest cracks and get close enough to his opponent to deliver a fatal blow. However, if he remains in this state for a long time, he can die from dehydration, as the salt gradually corrodes his body. The only way for him to restore his lost strength and human form is to dive into clean water.

Chikuma Koshino is a member of the Iga clan (筑摩 小四郎 Chikuma Koshiro) - despite the fact that in the Iga clan hierarchy, Koshiro occupied a position close to genin, his talent and fighting skills impressed the head of the Ogen clan enough that she included him in the list of ten elite shinobi representing the Tsubagakure clan in the fight against the Koga clan. Koshiro's special technique is the ability to create many small tornadoes, combined into one large whirlwind, which absorbs the enemy's body and breaks it into pieces. He also always carries two sickles (kusari-gama) with him, which he can use not only in close combat, but also in long-range combat, as boomerangs. After Gennosuke blinded Koshiro, the latter developed other senses to compensate for his blindness. Koshiro grew up with Oboro, and despite their families' different social statuses, she always considered him her older brother, and Koshiro was devoted to Oboro with all his heart. But on the other hand, he is Tenzen's disciple and is forced to follow his orders, sometimes suppressing his own feelings. Koshiro is also Akeginu's lover.

Akeginu is a member of the Iga clan (朱絹) - the kanji for her name literally translates to "red silk", which is the basis for her unique technique and clothing style. Akeginu is Oboro's personal bodyguard and confidante, and is the only one of the Iga who is calm about Oboro's failures in learning the art of war. Akeginu treats Oboro like a younger sister, but this does not stop her from deceiving Oboro when the Iga learn of the Iga-Koga treaty's breach and luring Gennosuke and Joshuke to her. However, Akeginu and Koshiro are the only ones of the top ten Iga shinobi who do not condemn Oboro after she sealed her eyes. Akeginu even specifically kept Gennosuke's flute, which he left for Oboro. An attractive and sexy woman, Akeginu is a prime example of a kunoichi, as she uses her sensuality to destroy opponents of the opposite sex. In battle, she uses a special technique that relies on controlling her own blood; by spraying her own blood into the enemy's face, Akeginu creates a mist and distracts them, thus gaining good conditions to attack. Akeginu is in love with Tenzen's student, Chikuma Koshiro, whom she would like to marry in the future.

Yakushiji Tenzen is a member of the Iga clan (薬師寺 天膳) and is the main villain of the anime and manga. After Ogen's death, he becomes the leader of the Iga clan. Despite the fact that Tenzen does not possess any special ninja techniques, a creature lives in his body that heals any wounds and restores after damage in battles. Tenzen can only be killed by burning his body to ashes or cutting off his head.

Ogen is a member of the Iga clan (お幻) - as the leader of the Iga Tsubagakure clan, she led a squad of ten Iga shinobi in a mortal combat with ten Koga shinobi. She has a telepathic connection with her falcon, which she uses as a messenger and servant. It is unknown if she has any special techniques. In her youth, she was in love with Koga Danjo, and together they wanted to end the bloody wars between the two clans by getting married. However, after the Iga clan was attacked by the combined forces of Oda Nobunaga and the Koga clan, which killed her grandfather, Ogen stopped trusting Danjo. Despite these events, Ogen in every possible way contributed to the marriage of her heir Oboro to the heir of the Koga clan, Koga Gennosuke, thereby trying to end the feud between the two clans. At first, she wanted Oboro to marry Tenzen, but then she changed her mind in favor of Gennosuke.

Oboro is a member of the Iga clan (朧) and is Ogen's granddaughter. She took over the Iga clan after her grandmother's death, but lost her authority due to her passive behavior. Her eyes have the ability to neutralize any technique.

Kazamachi Shogen is a member of the Koga clan (風待 将監, Kazamachi Shōgen) - Shogen has perhaps the most unusual body of all the characters featured in Basilisk. His spherical back, long arms and legs give him a spider-like appearance. He also has a long tongue (not as long as Jubei's) from which he can release a sticky substance. He can shape it into various shapes, such as bullets, threads, or even webs. Kazamachi is one of the few Koga who is more focused on combat than stealth. Kazamachi's body features are common to all of his line, as we can clearly see during the Iga's attack on Koga, when Koshiro encounters a shinobi who strongly resembles Shogen.

Jimushi Jubei is a member of the Koga clan (地虫 十兵衛 Jimushi Jūbei) - he has no arms or legs, but this does not prevent him from moving along the ground at high speed. To do this, he uses special armor on the chest of his tunic. Instead of arms, Jubei uses his long and prehensile tongue to attack, with which he pulls a dagger out of his throat and can stab his opponent with it. Jubei is also well-trained in astrology, and he predicted the future of the Koga clan with great accuracy.

Udono Josuke is a Koga clan member (鵜殿 丈助 Udono Josuke) - a kind, fat man with a good sense of humor; Josuke hardly fits the traditional idea of a ninja. And as we can see from his relationship with Akeginu, he is quite the rake. Despite his rudeness, Josuke is much more perceptive than he seems at first glance. He is the first to understand that the Iga are plotting something hostile towards the Koga clan. Despite his size, Josuke has excellent speed and agility: he easily dodged attacks by such strong shinobi as Akeginu and Rosai. Josuke's secret technique is the ability to change the shape and weight of his own body as he pleases.

Kisaragi Okoi is a member of the Koga clan (お胡夷, Okoi) - young and energetic, gifted with a beautiful body, she is a clear example of a kunoichi. She is related to Kisaragi Saemon, she is his sister, and Okoi is the only person who can make Saemon smile. In the anime, Okoi is very close with Kasumi Gyoubu, with whom they enjoy hunting animals in the forests of Manjidani. Despite her excellent ninja skills, Okoi has her own special technique: when making physical contact with a victim, Okoi's skin sticks to the victim's skin and she sucks out all of her enemy's blood. After using this technique, Okoi must remove excess blood from her body in order to use this technique again.

Kasumi Gyoubu is a member of the Koga clan (霞刑部, Kasumi Gyoubu) - tall, bald and muscular, he is capable of bending his enemy in half using only his arms. Despite his size, Gyoubu is considered an expert in the field of camouflage. By merging with the surface around him, Gyoubu can move freely across it and attack the enemy from where they least expect to be attacked. However, this special technique also has some limitations: firstly, the size of the surface used must be at least comparable to Gyoubu himself, so he can move freely in it; secondly, only his body has the ability to merge with the surface, so in order to use this technique he must be completely naked; thirdly, the fact that he merges with the surface does not give him any additional protection: if someone attacks the surface Gyoubu is in, he will receive a certain amount of damage comparable to the strength of the enemy's attack. Like most of the Koga, Gyoubu harbors a deep hatred for the Iga clan, but in his case, this hatred stems from a desire to avenge his father (Renbu), who was killed by Iga ninja. However, shortly after Renbu's murder, Hattori Hanzo forced both warring clans to sign a non-aggression pact, so Kasumi was unable to take revenge on her enemies. As a sign that he did not agree with the terms of the signed pact, he shaved his head bald. However, Gyoubu also admits his own guilt in his father's death, which he tells Hyoma. It was precisely because he was too weak at the time that Gyoubu spent his time training hard to create an insurmountable rock out of his own body. In the anime, Gyoubu maintains an almost familial relationship with Oka, who he always takes with him on hunts or just for walks in the Manjidani forests.

Kisaragi Saemon is a member of the Koga clan (如月 左衛門) and was chosen by Koga Danjo to be one of the ten shinobi who would represent the Koga clan in the mortal combat against the Iga clan. Saemon is perhaps the most complex character. Cold-blooded and indifferent, he can easily switch between military action and peaceful life. The only person he shows feelings for is Okoi, his younger sister. After Okoi's brutal death at the hands of the Iga shinobi, Saemon devotes himself entirely to the war between the two clans. For him, avenging his sister becomes on par with the well-being of his clan. He will use any means (physical or moral) to destroy the remaining ten shinobi of the Iga clan. But after each murder, Saemon asks for forgiveness from the victim and believes that in the afterlife his enemy will find the peace that he so lacked in life. Together with another shinobi from Koga, Kasumi Gyoubu, he specializes in disguise. By creating an imprint of the face of the person whose appearance he wants to take on in clay or earth, Saemon takes on the image of that person (having previously inserted the face into this imprint). Combined with the ability to imitate people's voices, Saemon remains an unrivaled master of disguise and espionage. But his technique has only an "external" effect: Saemon does not receive the abilities of those whose image he takes on, nor can he receive their memories. This technique does not work on animals (this could be seen in the situation with the snake Hotarubi).

Kagero is a member of the Koga clan (陽炎 Kagero) - a girl who is as beautiful as she is deadly. She is a master of the shuriken throwing technique and carries a sword that looks like a cane. The greatest danger lies in Kagero's breath, because when she gets excited, her breath becomes poisonous and anyone who is near her at that moment will die. All the women in her family possessed this technique. Kagero is in love with Koga Gennosuke, but because of her special technique and because of Gennosuke's love for Oboro, Kagero cannot be with him, which causes her great suffering. Oboro becomes Kagero's main target in the battle between the Iga and Koga. She tries to insult her at any opportunity, for which she often receives reprimands from Murogi Hyouma. Seeing Kagero's strong attraction to Gennosuke, Danjo consults with Hyoma before leaving for Sumpu that it is time to find a mate for Kagero. Despite Kisaragi Saemon's doubts that anyone would be willing to sacrifice their life for a night with Kagero, Hyoma believes that there are people in Koga who would be willing to do so.

Muroga Hyoma is a member of the Koga clan (室賀 豹馬 Muroga Hyōma) and is Gennosuke's uncle and mentor, having taught him the Eye Dojutsu technique. He is one of the ten shinobi representing the Koga clan in the mortal combat with the Iga clan. Hyoma's older sister is Gennosuke's mother, and he is Hyoma's nephew. Hyoma taught Gennosuke the Eye Dojutsu technique for many years. He always tried to show Gennosuke that one cannot rely only on the power of one's own eyes in battle, so he developed many other qualities in him that would be useful in battle. Unlike Gennosuke, Hyoma's Dojutsu works constantly, so he has to keep his eyes closed to avoid accidentally killing someone he shouldn't. Hyoma's well-developed hearing compensates for his lack of sight. Perhaps the most important lesson that Hyouma taught Gennosuke was his words about peace: "Despite all the differences that may exist between people, they are still people who live, feel, and die the same." It was largely thanks to Hyouma that Gennosuke was able to look at the feud between the Koga and Iga from a different perspective than the Koga people and tried to bring the two clans to peaceful coexistence. Hyouma, cautious and prudent, was the first of the Koga to realize that the non-aggression pact between the Iga and Koga was broken when the Iga entered Koga. Although Hyouma does not trust the Iga, he still fully supports Gennosuke in his desire for peaceful coexistence between both clans and supports him no matter what.

Koga Danjō is a member of the Koga clan (甲賀 弾正, Kōga Danjō) and is the grandfather of Gennosuke and the leader of the Koga clan. He was chosen by Tokugawa Ieyasu to lead the ten shinobi of the Koga clan who were to fight in a mortal combat against the ten shinobi of the Iga clan. He specializes in throwing poisoned darts, which he does almost perfectly. In his youth, Danjō fell in love with the head of the Iga clan, Iga Ogen. He wanted to marry her to end the centuries-old feud between the two clans, but a combined attack by Oda Nobunaga's forces and the Koga clan of Tsubagakure made his wish impossible. Despite Danjou not knowing about the impending attack on the Iga clan, the crushed Ogen could not forgive Danjou and their dream of peaceful coexistence remained just a dream. Despite his failed relationship with Ogen, Danjou never gave up on the idea of bringing the clans to peaceful coexistence. That is why he allowed Gennosuke to marry Oboro.

Koga Gennosuke is a member of the Koga clan (甲賀 弦之介 Kōga Gennosuke) - grandson of Koga Danjo, fiancé of Oboro. He became the leader of the Koga clan after his grandfather's death. He uses the Dojutsu eye technique ("bewitching gaze") and is also a skilled user of a katana. Dojutsu allows Gennosuke to instantly control the minds of his attackers, forcing those who meet his gaze to kill themselves instead of him.