Kyokotsu

Kyokotsu (Kyo means "evil/wicked") is the first of the seven to face a major character in the series. A giant undead human who loved to devour youkai, he terrorized the youkai-wolf tribes, who were defenseless before his size and invulnerability. Despite his massive size and fearsome looks, Kyokotsu is the weakest of the seven. He reeked of dead humans and graveyard soil. Koga, upon hearing that the northern clan was under siege, hurried back just in time to save some survivors. While fighting with Koga, Kyokotsu pulls a large flail-like weapon out of the ground and uses that as a weapon before Koga kicks the chain, shattering it, and rendering it useless. Kyokotsu is easily defeated when, while holding Koga with his hand near his face Koga simply takes the Shikon No Tama Shard out of his forehead, thus instantly killing him. Before Koga can get a firm grip on the jewel shard, it falls out and is taken up by a Saimyosho and given to Bankotsu.
Kyokotsu is, despite his appearance, a human. It's said that he become so big because of the youkai he ate. Unlike the other 6 assassins, Kyokotsu's shard is embedded in his forehead.
The marks on his face mean Power. He is the weakest member of the seven.
Jakotsu

A very loyal member of the Band of Seven, wielding a sneaky retractable snake-like sword named "Jakotsuto", Jakotsu (Ja means "snake") is one of the more skilled fighters of the Shichi'nintai and was placed third in command. He seems to be the first of the Shichinintai to have come into contact with Bankotsu and was with him before the Shichinintai were assembled as a group (in example, in Suikotsu's flashback we see that he was the only one with Bankotsu when Suikotsu was recruited in the Band of Seven). Bankotsu and Jakotsu are very close friends, and according to Bankotsu, Jakotsu is the only person he trusts. He is the first openly homosexual character in the InuYasha universe. He also seems to be a misogynist, since he resents both Kagome and Sango openly, especially the latter for interrupting a fight with InuYasha. Despite being a man, he has the mannerisms, appearance, and voice of a woman.
Upon hearing news of InuYasha from Kohaku, Jakotsu immediately develops a bloodthirsty and disturbing obsession with him. He spends the majority of the arc trying to find, battle, and kill him. After meeting InuYasha, Jakotsu is frequently swooning and petulantly protesting when he is denied confrontation. He also flies into a rage when Sango interferes in his first conflict with InuYasha, and at one point Jakotsu openly says he finds people like Miroku and Sesshomaru good-looking too.
Jakotsu always looks for an opportunity to fight against InuYasha. He finally gets a chance inside Mount Hakurei when InuYasha is reverted to his human form by the holy barrier. After a lengthy fight, Jakotsu loses to InuYasha (who has turned back in to a hanyou, due to the barrier), who spares his life. Badly wounded, Jakotsu happily accepted that he died after fighting the battle he wanted and having fun in his second chance at life, but could have survived if the Shikon shard embedded in his neck wasn't taken by the scheming Renkotsu. This action is later avenged by Bankotsu when he kills Renkotsu himself.
He uses a snake-sword (Kusanagi) resembling a machete that whips out several linking blades twisting and turning in unpredictable ways.
The marks on his face represent a snake's fangs, also meaning Death. He is the second strongest member of the seven. He is placed third-in-command, despite being physically stronger than Renkotsu, who is second-in-command. At the time of his first death, he was 20 years old.
Mukotsu

Mukotsu (Mu means "fog") is a short, and wide poison master, and the third Shichi'nintai that InuYasha and his companions meet. He abducts Kagome and, in the anime, tries to have a bizarre wedding ceremony with her but becomes angry at her due to her reaction to his facial features, and tries to kill her when she tries to remove his Shikon Shard. However, in the manga, Mukotsu tries to come onto Kagome until she stabs him in the with what looks like a fire poker. From that point on he tries to kill Kagome, until Miroku and Sango appear. Mukotsu poisons Kagome, Miroku, and Sango, nearly killing them, but was soon killed by Sesshomaru, on whom his poisons have no effect.
He uses a variety of poisons and acids kept in wooden tubes to both attack and weaken his targets and protect himself. He can even blow small clouds of toxic smoke from his mouth.
The marks on his face mean Poison. He is the sixth strongest member of the seven. His appearance and clothing are somewhat similar to Genma Saotome, the father of the main protaganist from Ranma 1/2.
Ginkotsu

A mechanical-man, Ginkotsu (Gin means "silver") is a tough opponent even for the Wind Scar to defeat. Not much for talking, he commonly is heard merely saying "yesh", "gersh", "gesh", "yersh", "nosh" (for "no" mumbled incoherently) but when angered, taunting his opponents, or speaking to Renkotsu he does use actual words. He barely survives his first encounter with InuYasha and is reconstructed into a siege tank with spider-like legs thanks to Renkotsu. Later, he fought Koga with Renkotsu. In the manga, he exploded when Koga had stuffed pieces of armor into his cannons, causing them to backfire. In the anime, he survived this attack, but went berserk when Renkotsu received a heavy wound to his left shoulder, causing Ginkotsu to unleash every weapon he had on Koga to no avail. Ginkotsu then self-destructed in an explosion while shielding Renkotsu with his own jewel shard in an effort to save Renkotsu's life.
While in human form, he carries a katana (which he rarely uses), an axe attached with a chain, a spear (which only appeared at his introduction), wires to prevent an enemy from moving, a grappler that replaced his left arm which he launches to bring enemies towards him or scathe them, disk-blades that cut an enemy and return to their slots, a cannon on his shoulder and that can fire cannonballs and shrapnel blasts, and a drill in his chest.
In his tank form, his offense is two main cannons. For movement, he has spider-like legs along with disk-blade wheels. In the anime, his additional weapons include a larger array of firearms, as well as launching his main body off like a rocket, which contains wire launchers and a flamethrower. His final weapon is a self-destruct mechanism.
He is the only one of the Shichinintai that does not have distinguishable markings. However, the remains of his markings resemble the Eye of Horus, which means Protection, which fits his armor theme.
He is the fifth strongest member of the seven.
Renkotsu

Agile fire and explosive user, Renkotsu (Ren relates to "metalworks") is the second in command and one of the more intelligent members of the Shichi'nintai. He respects his leader just as much as any other member of the Shichi'nintai. However, with the corrupt power of the shard of the Shikon Jewel embedded in his neck, and being forced to give up any extra Jewel Shards to Bankotsu, he starts to feel hatred and jealousy towards his leader and vows never to die again because of him by any means necessary. To do this, he requires possession of all the Shikon Shards Naraku gave them.
Renkotsu is first of the Shichi'nintai to find out some truth about Naraku and reasons that Naraku is not to be trusted. He finally comes to the point where he believes he is better than the others and eventually becomes a little overconfident. After taking Jakotsu's shard (who was defeated by InuYasha) and killing him, Renkotsu tries to kill Bankotsu, who has found out about Jakotsu after an insect brought him Jakotsu's hairpin. He fails, and Bankotsu takes Renkotsu's jewel shards, killing him, and leaving Bankotsu the last of the Shichi'nintai. In the anime he actually lived just a little longer than in the manga, being told to fight first by Bankotsu before he was killed by him.
He is an expert with explosives and metallurgy who used bombs, cannons, and other artillery; created fire from his mouth by drinking a liquid (oil) from a calabash bottle and alternatively from what seems to be a crude form of flamethrower; set wires hooked onto his hands on fire, thus pulling his victims into a net of fire. He was also a gifted strategist, and possessed some skill at hand to hand combat although the only member of the group he surpassed in fighting skills was Mukotsu. He was also skilled at mechanical work, to the point of being able to reconstruct Ginkotsu into a living artillery weapon resembling a modern tank, giving the series a anachronistic look. His only weakness is the fact that he needs to carry around his contraptions which could affect his mobility.
The marks on his face mean Deception. This could be related to his apparent ability to make his markings disappear in order to deceive InuYasha into trusting him to be alone with the poisoned and unconscious Kagome, Miroku, and Sango. This may also relate to how he sought to betray Bankotsu.
He is the fourth strongest member of the seven, and the most intellegent one.
He is placed second-in-command, despite being physically weaker than Jakotsu, who is third-in-command. At the time of his first death, he was 24 years old.
Suikotsu

Suikotsu (Sui means "sleeping") has two personalities: "Doctor Suikotsu" is good, kind, and respected by villagers; and "Suikotsu of the Band of Seven" is evil and blood-thirsty. Suikotsu of the Band of Seven tends to emerge when exposed to a great deal of violence or blood. The violent personality emerged as a result of Suikotsu's prolonged exposure to war and killing a soldier both in self defense and as punishment for murdering a little girl whose life he was trying to save. Hakurei-Zan (Mount Hakurei)'s purity tends to favor Doctor Suikotsu. After transforming into both forms, he emerges back at the village he practiced at without the markings on his face, but still violent and willing to kill. He mentions to Jakotsu that he "feels better than ever before" and that he "feels alright now" instead of the two sides fighting inside of him, implying that there may be a third personality, or at least that his two personalities may have become one singular being. He was soon beaten by both Sesshomaru and Kikyo's sacred arrow when he used Rin as a hostage, and, after explaining how he had overcome his double personality, asked Kikyo to remove the Shikon Jewel shard from his neck and let him die peacefully. Respecting his wishes, Kikyo reached to retrieve the jewel, but was stopped as Jakotsu removed it himself and took it to Bankotsu. He shared an impulsive yet close relationship with the Miko, Kikyo. It can be speculated Suikotsu had deep growing feelings for her.
He uses a pair of shuko, neko-te tekagi, or handclaws on each hand with exceptionally long blades. He also possessed phenomenal strength, agility, and savage combat skills due to his unique form of mania and bloodlust.
The marks on his face means Rage. These marks only appear when he is the Evil Suikotsu. He is the third strongest member of the seven. At the time of his first death, he was 26 years old.
His steel claws and hair-style while in his evil form are similar to Wolverine from the X-Men series.
Bankotsu

Bankotsu (Ban means "barbarian") is both the most powerful and final member of the Shichinintai to make his presence felt. Naraku revived him with a Shikon shard and ordered him to kill InuYasha, but his first order of business is retrieving Banryuu, his halberd, that had been taken by the lords that beheaded him and the Shichinintai 10 years prior. Once he does, the Shichinintai slaughter everyone else in their surroundings.
The scent of bloodshed from that battle draws InuYasha and company to Bankotsu, who has the Jewel fragments of his fallen comrades Kyokotsu and Mukotsu. Bankotsu was able to fight InuYasha without backing down, but soon realized that he was not powerful enough when his halberd was nicked by InuYasha's Wind Scar. He took the jewel shards Renkotsu stole from Kagome to repair his damaged blade, giving it the power to deflect the Wind Scar easily.
Bankotsu soon realizes just how deceptive Renkotsu has become, killing him when he learned Renkotsu murdered Jakotsu (in the manga, immediately after such a blow; in the anime, after a short duel). Now with 7 fragments in his body and two in his halberd, Bankotsu headed off to destroy InuYasha once and for all deep inside Mount Hakurei. In the manga, InuYasha slowly cuts the Shikon shards out of his body as the battle progresses until Bankotsu was cut in two, with Naraku stripping the remaining half of its shikon jewel shards.
By defeating Renkotsu who challenged him, Bankotsu obtains all of the 7 Shikon Shards given to the Shichi'nintai by Naraku, in addition to the 4 shards he took from Kagome and embedded in his weapon in episode 111 . A total of 11 shards were in his possession and his strength increased immensely. In the anime, Bankotsu slew 1,000 youkai including 9 inside Mount Hakurei, and killed 1,000 warlords with his halberd Banryuu. Banryuu, in turn, transforms into a demonic weapon ability to release physical manifestations of its users' hatred in the form of powerful demonic energy. However, this proves to be his downfall as InuYasha takes the opportunity and unleashes the Backlash Wave, crushing Bankotsu and shattering Banryuu. This attack and the more power-obsessed Bankotsu are only in the anime. In the manga, InuYasha simply slashed Bankotsu in half at close range.
Bankotsu broken up into "Ban" and "Kotsu" means "Barbaric bone." Bankotsu can also mean "reckless youth".
Bankotsu wields "Banryuu". Banryuu is described in the anime as a halberd, when it actually resembles a huge double edged broadsword. The following is a list of its attacks:
"Banryuusen": Bankotsu can use an attack almost identical to InuYasha's Wind Scar except it's pink. This is basically kenatsu (sword pressure) with a name. He only uses this attack in Episode 113 of the anime: "The Sacred Vajra and the Mystery of the Living Buddha".
"Ryuuraisen": Bankotsu is able to summon a thunderstorm and manipulate the lightning creating a number of lethal electric bolts that almost kills everyone on Hijiri Island. The attack cannot be fully controlled, and hits randomly around Bankotsu. He only uses this attack in Episode 113 of the anime: "The Sacred Vajra and the Mystery of the Living Buddha".
"Heat Blast": (This attack has no name, and the given name is unofficial.) In Mt. Hakurei when InuYasha and Bankotsu battle for the last time Bankotsu uses a series of flaming ball-like flashes that burn everything in sight, it even destroys most of the rock walls in the mountain.
"Hatred Ball": (This attack has no name, and the given name is unofficial.) Bankotsu's most powerful attack, Banryuu's ultimate attack. The hatred built inside the halberd combined with the power of the 4 shikon shards inside Banryu creates a huge and powerful ball of swirling anger and fire. However, this all-powerful attack is his downfall: InuYasha uses the Bakuryuuha to shatter the Banryuu and then the Hatred Ball consumes Bankotsu. He only uses this attack in Episode 122 of the anime: "The Power of Banryuu! Duel to the Death on Mt. Hakurei".
Kenatsu: Aura waves produced by the sacred shards embedded within Banryuu. In episode 112 it was blue, in 113 it was pink, and in 122 it is red, fueled by emotions, thus much more powerful.
The marking on his forehead represents Youth. He is the leader, and the strongest member of the seven. At the time of his first death, he was 17 years old making him the youngest member of the Band, though most of the Band refers to him as "Big Brother".
His black hair in a pig-tail may be a reference to Ranma Saotome; the main protagonist of Takahashi's previous series: Ranma 1/2.