Naraku

Naraku (奈落, Naraku; translated as Hell) is the main antagonist in the anime and manga series InuYasha. He is directly responsible for the death of the character Kikyo and the seal placed on the series' protagonist, Inuyasha. He is also the cause of most of the troubles and problems facing the other major characters, making his destruction the overall focus of their quest due to the pain he has personally caused them.

As half-demon and later a demon, Naraku desires the Shikon-no-Tama, a jewel that would be able to grant him near-invincibility should he acquire all the pieces of it. Although early in the series he desires the jewel to purge his half-human self from his body, he desires the jewel to enhance his strength even further. He is repeatedly opposed by InuYasha and his friends, along with several other characters in the series.

Onigumo
Once, there was a man named Onigumo (鬼蜘蛛, おに ぐ も,oni kumo onigu mo "demon-spider"), who was full of deceit and hatred for others. The manga tells us almost nothing about his life before he meets the protagonists, but the anime adaptation shows him in a flashback associated with a group of roaming thieves. It tells how he tricked his bandit leader, Rasetsu (the elderly man in the anime who gives Kikyo his top knot to be sent to Mount Hakurei in order to purify his soul) into approaching Kikyo and attempt to obtain the Shikon no Tama, or Jewel of Four Souls; however, Onigumo did not warn him that with Kikyo, there was a half-demon named Inuyasha. Rasetsu survived the encounter with Inuyasha, lost an eye, and returned to his camp only to find that Onigumo had made off with his troops. Rasetsu discovered Onigumo and his troops at an inn down the road celebrating their change in leadership. Enraged, Rasetsu blew up the inn, but the charred body of Onigumo somehow managed to survive the blast. Rasetsu then threw the barely-living Onigumo off a cliff. (This, however, does not explain his spider scar, as Onigumo had the scar before he met Rasetsu).

By either chance or fate, the badly burned Onigumo was found by Kikyo, who slowly nursed him back to the point of being able to speak. Onigumo developed feelings for Kikyo, but knowing that he could not move for the rest of his life, he summoned countless demons using his corrupted soul. He then had them devour his body in exchange for giving him a new body with which he could claim Kikyo and the Jewel of Four Souls. Thus the countless demons were bound together in one body with Onigumo serving as a connector.(In an anime special, it is implied that a spider demon, which looked like a small replica of Naraku's spider form in the second movie, was in fact the leader of these demons.) This resulted with Onigumo being reborn as the half-demon Naraku.

Evolution of Naraku
In the meantime, he did not forget about his ultimate goal of obtaining the corrupted Shikon no Tama. He disguised himself as both Inuyasha and Kikyo and tricked them into hating each other, as he describes that "the Shikon Jewel is the most beautiful when it's tainted by the hatred Kikyo and Inuyasha have toward each other".

He mortally wounded Kikyo while disguised as Inuyasha, took the Shikon no Tama and returned it to the village, then disguised himself as Kikyo and attacked Inuyasha. Inuyasha, sensing something was wrong, instinctively went back to the village to retrieve the Jewel. However, disguised as Kikyo, Naraku told the villagers that Inuyasha would come for the Shikon no Tama at any cost, thereby forcing Inuyasha to use force to obtain the Jewel. As he was getting away with the Jewel, Kikyo, with her remaining strength, sealed Inuyasha to the Tree of Ages. Naraku, who desired both the Jewel of Four Souls and Kikyo, thought that she would use the Jewel to heal herself, but instead she requested Kaede to cremate the Jewel along with her dying body, so that it would be taken to the afterlife with her.

Onigumo's soul, within Naraku, objected to Kikyo's death. At this time, Naraku took action to prevent Onigumo from consciously influencing the half-demon's actions. Onigumo perceived this process as imprisonment in a deep dark place where he proceeded to sleep.

For fifty years after Kikyo's death, Naraku secretly plotted and waited for the Shikon Jewel to appear again. After the appearance of Kagome as the present-day reincarnation of Kikyo and Inuyasha's awakening, he moved forward with his plan of gathering the shattered shards of the Jewel. Knowing his weakness as a half-demon, he relied mostly on evil tricks and traps while gathering information on his potential enemies that would stand before his insidious plot.

Being a half-demon like Inuyasha, Naraku also sometimes experiences a period of weakness. During those times, he loses all his demon powers and reverts to his human "form". While in this form, he is composed of his head attached to countless random demon parts. Naraku has the freedom of choosing this time, unlike Inuyasha, and since he is made up of thousands of demon, each time he "experiments" and "reconstructs" his body, he gets rid of weak and useless parts while keeping the vital ones to get stronger. It is possible that during each of these periods he expelled more and more of his humanity. This process ultimately led to the creation of his stronger form.

Disposal of his human heart
After InuYasha was able to break his barrier with the red Tetsusaiga, Naraku was greatly injured. He then retreated to Mountain Hakurei for many months. While he was reconstructing his body, he resurrected the Shichinintai to keep his enemies occupied. To better protect himself from powerful demon enemies like Inuyasha, Sesshomaru, and Koga, he deceived the lost soul of a dead priest, Hakushin, into creating a barrier so holy, that it would purify and cleanse any demon that came close to it. The closer Naraku's enemies came to the core of the barrier, the stronger it's effect was. This was also the most powerful barrier in the series as its reach extended over the perimeter of an entire mountain and much of the land around it. The stronger a demon, the deeper into the barrier they could go until they got to a specific sort of critical point where anything with even the slightest bit of demon energy would be utterly purified. Naraku himself hides within a cave inside the mountain which is not affected by the purifying barrier. Kikyo gently persuades Hakushin to remove the barrier. After the barrier vanishes, his soul ascends to Heaven.

When Naraku separates himself from his heart, it renders into two pieces. The physical heart (心臓, shinzou) he imparts to one of his incarnations, "The Infant", rendering Naraku effectively immortal unless The Infant is destroyed. The spiritual heart, or soul (心, 'kokoro'), which he inherited from the human Onigumo, is discarded inside Hakurei. In the process Naraku becomes stronger, much like a full demon. (Comments later made by Abi and Tekkei revealed that Naraku was still technically a half demon). Furthermore, he now possessed an even stronger personal barrier than before, which would prove impenetrable to anything except for the Tetsusaiga's Kongōsōha Adamant Barrage. Naraku then takes advantage of his heart's absence and strikes down Kikyo.

Re-absorption of Naraku's heart
Following the death of Kagura in the manga, Naraku becomes largely absent from the series, and the focus shifts to Akago's and Mōryōmaru's quest to absorb demon and Shikon shards. Naraku finally reappears, reviving a tree demon known as Yōmeiju, a tree which devoured humans and demon alike. But this time, as Inuyasha and his group watched, Naraku devoured the tree. Shortly thereafter, he and Mōryōmaru squared off for the first time in an open battle. Naraku then reveals that the reason he created Akago as an infant and purposely made him so weak, while providing him with a powerful barrier that he had the power to disable, was because he always knew his heart would turn against him. Taunting Mōryōmaru about his shell, referring to it as a castle and to Akago as a king who has grown fat inside a castle, Naraku at first appeared to be trying to reabsorb him. But this clash ended with a shocking twist: Mōryōmaru absorbed his maker, supposedly defeating him for good. Naraku soon revealed that he was in fact alive, having allowed Mōryōmaru to absorb him in a Trojan Horse-style ploy in order to then devour Mōryōmaru from the inside. He then used the Yōmeiju's barrier-dissolving abilities to reclaim Akago and then fully assimilated Mōryōmaru into his being.

In Chapter 452 of the manga, "Spider Web", Naraku returned to Hakurei-Zan to reabsorb the heart of Onigumo which he discarded there. Onigumo speaks to him, gloating that Naraku still needs this discarded human heart to avoid being purified by Kikyo, because of Onigumo's intense negative feelings. The human heart says it possesses more intense negative feelings, and these can prevent purification by bringing darkness to the Shikon Jewel. Naraku seems to confirm this analysis. He intends to exploit the emotional connection between the hearts of Onigumo, Kikyo and Inuyasha to destroy both Kikyo and Inuyasha. The re-absorptions may mean that Naraku has lost the invulnerability he obtained from keeping his heart outside his body. However, the Shikon no Tama also allows it's possessor to survive otherwise fatal injuries. The diamonds on Naraku's new body, along with his armored shell, may also add some extra protection (due to the former being the hardest substance on the planet, and the latter easily able to swat off even the destructive brunt of the Kongōsōha).

The Shikon Jewel's Completion and Death
In chapter 463 while battling with Inuyasha, Naraku takes Koga's shikon shards because he placed his Jewel shard inside Kikyo. After he placed it in Kikyo, Kagome shot Kikyo with her last sacred arrow to purify her, then Naraku used Koga's shards to corrupt the Jewel as Kikyo plans to purify the Jewel. But Naraku's evil overpowered Kikyo's holy aura and allowed him to reclaim the Jewel, leaving only Kohaku's shard.

However, in chapter 475, Naraku blames Kikyo for a purity inside the Shikon Jewel. To prevent him from losing, he forced Kanna to sacrifice herself to destroy Tetsusaiga. However, Kanna told Kagome about the light in the Shikon Jewel instead.

He is dead-set on decapitating Kohaku in an attempt to get his shard without becoming purified by Kikyo's presence in the jewel, however a light from the shard prevents him from doing this. The light/purity of Kohaku's shard (though Kohaku needs the shard to stay alive) is the work of Kikyo but whether it is her soul or her "light" is a matter of debate.[citation needed] Magatsuhi, the demon sealed inside the Shikon jewel by Midoriko, escapes the gem and creates a new body for itself using some of Naraku's spare parts. Technically this would mean he is not truly Naraku's as he reveals he is merely borrowing a body from Naraku. Magatsuhi is able to, in contrast to Naraku, not only touch the shard in Kohaku's back, but corrupt it as well. In chapter 528, Naraku succeeds in removing the shard from Kohaku, though Kohaku is able to survive the loss of his shard with the help of Kikyo's light.

Naraku completes the Shikon-no-Tama and uses the fully dark jewel to begin his final transformation. Before that, when asked by Byakuya what he would do with the jewel, Naraku admitted that he had no real plans for it and wondered what would be left for him when he killed all the people who hated him. Following his completion of the Shikon no Tama, Naraku takes on the form of a gigantic spider. However, within this new body his opponents meet several variations on his traditional humanoid form. After the defeat of Magatsuhi by Inuyasha and Sesshomaru, Kagome's spiritual powers return and a small light returns to the once completely corrupted Shikon Jewel. Naraku planned to use the hope of this light to trick Miroku into killing the others with the last use of his Wind Tunnel. Although things do not go as he originally plans, Naraku finally eliminates the last traces of light within the Shikon-no-Tama and fully fuses with the jewel.

Kagome asks Naraku what his true wish was, since it seems that the Shikon-no-Tama has not granted it. This question startles him greatly. Inuyasha tells Naraku that he seems to know a lot about relationships because he focused so much on tearing people apart, and mentions that this is because of his human heart, which the Shikon Jewel may not have removed. For the first time, Naraku hesitates to attack Inuyasha and Kagome. Inuyasha attacks him with a variation on the Meidou Zangetsuha more adapted to his fighting style, and seems to damage even Naraku's most powerful form. Although he regenerates from this repeatedly, Sesshomaru takes note of Naraku's vulnerability and uses the Bakusaiga on him. Because of Bakusaiga's decomposing powers, Naraku's large outer body begins to fall apart. As Naraku weakens, the curse on the Wind Tunnel begins to break as well, and Miroku uses it to absorb much of the deadly shouki.

Naraku becomes cornered as much of his body deteriorates, he uses the Shikon no Tama to grant him more power. He uses this power to stall the others from killing him so he can prepare to crash his gigantic, shouki-filled body into Kaede's village. Though he intends to use this threat of destroying the village to prevent Inuyasha from killing him, Sesshomaru ignores him and strikes his main body with the jewel with Bakusaiga. Sesshomaru's sword, however, doesn't even scratch the jewel, which prevents Naraku's death. As his massive body begins to fall onto the village, everyone escapes from within and tries to protect the villagers. Kagome sees the Shikon no Tama within Naraku and shoots an arrow at the jewel. Prior to the arrow hitting the jewel, Naraku thinks to himself that indeed the Shikon no Tama did not grant his true wish: he wanted Kikyo's love, and laments that he won't be able to go where she is in the afterlife. Naraku's body is completely purified and most of the village is saved from destruction.

Naraku, appearing as only a head above the pierced jewel, hovers above the bone-eater's well and says he made a different wish upon the Shikon no Tama earlier in the battle, and that when he dies that wish will be granted. He finally dies, and a stolen meidou appears to swallow Kagome as the well disappears. It is revealed the wish Naraku made was actually the wish of the Jewel itself: that the souls of Naraku and Kagome would replace it and Midoriko, or merge with them, continuing their battle inside the jewel. This revealed that Naraku was, in fact, another pawn of the Shikon Jewel's quest to maintain its own existence, making the Jewel itself the real antagonist of the entire story. But with help from Inuyasha, Kagome instead makes the Jewel vanish or turn into light. In the manga, what became of Naraku's dead form is never revealed; but in the anime, Naraku's dead form, inside the Jewel, briefly awakened, remarking that he feels warm and is at peace before disappearing forever.

Appearance
Naraku takes form of a young lord, Kagewaki Hitomi. He then controlled a body underneath a white baboon cloak-like outfit. Later on, he dresses in a simple, common outfit. It was dark blue with a purple vest on top. Once gaining more power, his appearance changed completely. His outfit then turned purple and light blue, but with boned armour. It has green tentacle-like arms coming from his back, which has large hoop bones which leads to a red-eye on his chest. He takes this appearance throughout the rest of the series.

Power & Abilities
Naraku's minion wasps from hell. They are useful for stopping Miroku's Wind Tunnel, spying on his enemies, and gathering Jewel shards. Their stings are fatally toxic to both humans and demons alike, but they are rather weak as demons come and are thus easily and numerously slain by InuYasha's group.
 * Saimyōshō

He can take the form of anything he chooses (usually a humanoid), and change his voice along with his physical appearance. He can also change his body however he wants. This is seen when he fights Sesshomaru in an attempt to absorb him and when he fights Moryomaru to reclaim Akago.
 * Shapeshifting

Puppets which resemble him. He controls them from afar and can see through their eyes. They are mostly made of mud and soil, and are able to spring roots in order to attack opponents. Much like Sesshomaru, Naraku is far stronger than a normal demon and can move faster than the eye can see, both in the air and on the ground.
 * Demon puppets
 * Superhuman strength and speed

Similarly to Sesshomaru, Naraku possesses the ability to float midair, and to ride upon a cloud of his own shoki. After his transformation into a full yokai, Naraku never chose to employ his shoki-sustained flight, but flew only by the strength of his will.
 * Flight

As he is made up of multiple demons in one body, Naraku is able to manipulate their body parts at will in order to restructure and strengthen his body, and he can also regenerate himself from injury and reform his body parts if they are cut off. He most commonly uses these parts to form tentacles which he uses to attack.
 * Demon parts

Naraku is able to absorb other demons into his body, adding their powers and body to his own. This is primarily how he gains strength, by seeking out and absorbing strong demons, giving him access to their powers. Naraku can also expel weaker body parts in order to rid himself of them.
 * Absorption

Naraku has shown using various psychic powers and capabilities; including levitation, telepathy, telekinesis, teleportation, mind control, illusion-casting, and astral projection.
 * Psionics

He can make incarnations out of his own body to do his dirty work for him. Most have a spider mark on their back which is a result of being born of Naraku when he still was a han'yō with Onigumo inside him. After he purged himself of his human presence in the countless lumps of flesh inside Mount Hakurei, he and all his future children were free of having that scar on them.
 * Detachments

A barrier which prevents the foe from finding and/or attacking him. At first his barrier was only useful in hiding his presence. As he persevered in absorbing new, stronger demons into his body and discarding the weaker ones, it became powerful enough to survive the Kaze no Kizu, which is why Inuyasha needed to obtain blood from the bat demon, Taigokumeru, in order to penetrate. After Naraku became a full demon (in a sense) the barrier became so powerful that nothing but the Kongōsōha was able to pierce it.
 * Barrier

Whenever someone sends an attack of yōki (demon energy) into Naraku's barrier he can channel the flow of the attack into his own jaki (yōki aura) and then attack his opponents with it. However, this can only be done with attacks that cannot penetrate his barrier, which means it's useless against Inuyasha's Kongōsōha.
 * Demon Control

Naraku can quickly heal his own wounds and also put back together severed pieces of his body. He can control 100% of his body all the time (even when severed), which comes in handy when he is trying to absorb someone. However, there is a limit to how much he can regenerate. The more damage he takes, the more time he will need later on to recover. Too much damage can kill him, which is why he had to flee from his enemies in the beginning of the series. Usually, he will absorb demons to speed up his regeneration process. However, after he removes his heart, which comes out as Akago, he was able to regenerate no matter how much damage his body took since his life force wasn't in his body.
 * Regeneration

Unlike Inuyasha, who is forced to become fully human on the first night of a new moon every month, Naraku, as a half-demon with Onigumo inside him, could choose what time of the month he lost all of his powers and became human, although he was merely a human head attached to a mass of yokai parts during this time, which he used to experiment with his body and rid himself of any unnecessary parts. Since the events that have transpired on Mt. Hakurei, he no longer has to become human at any time, being a full-fledged yokai.
 * Human/Demon shift

Naraku sends out one or more of the horns on his elbows in a zigzag beam attack or extends his fingers into tentacles with a glowing attack at the tip of fingers to attack his foe(s). In the manga this attack was of a silverfish color and in the anime it is of a purple color. Furthermore, even though this attack is a yōki attack, because Naraku is using his body parts infused with shōki to attack his opponents, Inuyasha cannot use his Bakuryūha (Backlash Wave) against it since it counts as a physical attack.
 * Beam attack

Naraku's trademark, a poison which kills anything that touches it. It's what makes his poisonous gas. Naraku uses it to cover his entrances and exits, and can surround himself with the gas while flying. He created a "false Shikon shard" for Kōga with this substance. It was able to power Kōga in the manga and anime for a while until it backfired, poisoning him, and ultimately leading him to remove it with the help of Kagome. Naraku's body is filled with it, which is why when a foe bites him or even touches him he/she gets poisoned. Later on, as his power grew upon his transition to full demon, his shōki is able to take on a liquid form and acts like a river of acid. His shōki is so strong that it allows him to break away pieces of the nearly completed Shikon no Tama to use in his schemes. In the current manga, he can melt entire mountains. Over time his shōki has become so dangerous that after he infects Kikyō with it, neither Kagome nor Kikyo's holy powers seem to be able to purify it. Kikyo absorbs Midoriko's soul in order to protect herself but she comments that she doesn't know how long Midoriko's power can last against Naraku's venom, in the regard that she and Midoriko remain at the same strength while Naraku continues to increase in power. Eventually, even the influence of Midoriko is nullified with Naraku's absorption of the tree and Mōryōmaru.
 * Miasma

After absorbing Akago/Mōryōmaru, Naraku gained the power to merge pieces of his body with other demons, thus giving him control over them and increasing their regenerative abilities. He can send pieces of his body abroad to scout for new demons, for him to add into his body. It is important to note that these pieces, after becoming separate of Naraku's body, became living beings that can move and fight on their own.
 * Live Body Pieces

This power is only displayed in the Playstation 2 RPG InuYasha game; InuYasha: Secret of the Cursed Mask. He obtained this power by deceiving Utsugi, a 'hitogata' (clay doll demon) duplicate of the original Utsugi, who was created by the priest Kakuju to ease his/her suffering when his/her real wife/husband died. Utsugi (the hitogata) required the soul of a relative of the real Utsugi, and a large portion of the Shikon Jewel, which Naraku provided, and helped in retrieving shards from Koga to become a true, live human. When Naraku supposedly died (w/ jewel on hand) at the hands of Inuyasha & co, the leftover jewel was retrieved by Utsugi behind the scenes. When Utsugi finally retrieved the soul she/he needed (which as it turns out, was Kakuju's) Naraku's voice began echoing from the Sacred Jewel, and Naraku took over Utsugi's body rather than absorbing her/him to acquire her shikigami-channeling powers. He became able to use the destructive power of an unknown variety of shikigami, and would time-to-time spout out a long verse when he attacked during the fight in the game. Because this only happens in a game based on the anime (which wasn't entirely canon from the start) and the events of the game stray away from the actual cliffhanger ending of the anime, this power is un-canon.
 * Shikigami

Naraku is seen having the ability to create various "Phantom Castles" as a temporary headquarters throughout the series.
 * Phantom Castle

Naraku has the ability to hide himself within one of his servants and make it appear as though he has disappeared, or have been killed, rather. A simple task; he gets himself "killed'" and hides within the body of a servant of his choice.One of the first times we see this is in the second movie when he hides in Kohaku's back he seems toleave a spider mark like his on who ever he lays dormant in. To reinforce this fact, he even (although temporarily) removes Miroku's Wind Tunnel and returns Kagura's heart.
 * Dormancy

Naraku knows many different spells and curses, a prime example being the Wind Tunnel.
 * Black Magic

Upon absorbing Mōryōmaru, he gained the ability to cover himself at will with Mōryōmaru's impenetrable shell. It has been revealed that Naraku is hiding the Shikon Jewel underneath this shell.
 * Armor Shell

Detachments
To get rid of unnecessary parts as well as keeping a better eye on his surrounding situations, Naraku was constantly releasing detachments of himself to carry out his bidding. Only a few of the detachments truly live up to their purposes as most betrayed him or were quickly disposed of by the people going after him. As of Chapter 548, with the death of Byakuya, Naraku no longer has any detachments:

Kanna is an albino girl that barely speaks. She is a demon of mu, "void" or Goddess of Void. Kanna comes from an old word meaning "godless world." She is Naraku's first detachment, and remains utterly loyal to him while knowing that they are just used as tools in his schemes. Representative of the void in which she controls, Kanna herself is completely devoid of any emotion, never questioning any orders given to her by Naraku. In chapter 480, after a failed attempt to destroy Inuyasha's Tessaiga, Naraku orders her to commit suicide by shattering herself—as a final attempt to destroy Inuyasha's group (In the anime he destroys her heart). In her final moments, however, Kanna seemed to display some signs of emotions, as if she really did not wish to die. It is in her death that she commits her only act of defiance to Naraku: As a shard of Kanna's shattered body flies into Kagome's eye, Kanna uses this opportunity to show Kagome the light that is present within the Shikon no Tama, which could be the key to defeating Naraku.
 * Kanna

Kagura is a powerful wind sorceress and appears first in the manga and anime, though she is his second detachment. Naraku endlessly uses her as bait to test the enemies' strength and, aware of her betrayals, keeps good watch over her. Her storyline is constantly followed as she plots to destroy Naraku and win back her heart, often in combination with Sesshomaru. Eventually, she is killed by Naraku after she openly betrays him to protect Kohaku.
 * Kagura

The third detachment of Naraku, Goshinki was a large horned ogre with the ability to read minds. He was extremely agile, very powerful, and had teeth so strong they ultimately broke the Tessaiga, which ended up being his own undoing as InuYasha transformed into a Yokai. After being defeated, Sesshomaru contracted Kaijinbō to create Tōkijin from the fangs of Goshinki's head once the head was resurrected.
 * Goshinki

He was a feral detachment and brother of Kagerōmaru, who lived in his stomach. He and his brother Kagerōmaru were both killed in battle by Inuyasha with Kaze no Kizu (Wind Scar).
 * Juromaru

He was a small, fast and intelligent detachment from Naraku. He lived inside Juromaru. He was not particularly loyal to Naraku. He and his brother Juromaru were both killed in battle by Inuyasha with Kaze no Kizu (Wind Scar).
 * Kagerōmaru

He was born as "the man with no face", a reincarnated Onigumo. He was reabsorbed after a short time of independence.
 * Muso

He is a child that has the ability to corrupt the hearts of people into doing his bidding. He was cut in half by a priest, which led to the creation of Hakudōshi. After being cut in half, the left half (which remained to be Akago) was taken by Kanna, and Kanna told Kagura to take the right half (which became Hakudōshi). He later is placed inside the haku (life force) puppet, Mōryōmaru. In Chapter 446, Mōryōmaru is taken over by Naraku. In Chapter 448, Naraku disappears with Akago, and by his next appearance in Chapter 452, has reabsorbed him. NOTE: The status of Akago as this character's actual name is contested, since akago is standard modern Japanese for baby (whereas all the other characters' names have obscure and / or archaic meanings). In the official English translation, he is called "the infant".
 * Akago

He is an incarnation from Akago. Hakudōshi literally means white child. Taking the form of a young child, he was able to tame the horse demon Entei. He continues Akago's quest to get the last Shikon shard. After Naraku is nearly destroyed at the boundary of the afterlife, Hakudōshi is charged with flushing out Kikyo. He eventually is found out as a traitor to Naraku and is sucked in by Miroku's Kazaana.
 * Hakudoshi

Naraku's incarnation that first appeared in Chapter 397. He told the Dokumizuchi, who had eaten Mōryōmaru's flesh, the location of Inuyasha. He was created to replace Kagura, serving the purpose of tracking down Mōryōmaru while keeping tabs on the full-extent of Inuyasha's Tetsusaiga. Byakuya uses origami as his primary weapon and seem to be able to create illusions, but not much else was known about him. He was killed when Inuyasha used the Cutting Meidou on him after he attacked Kagome.
 * Byakuya

Other
The demon sealed within the Shikon Jewel centuries ago, it appears in Chapter 513, borrowing flesh from Naraku to craft a temporary body, an armored man with white hair and claws. Upon being free, Magatsuhi attempts to kill Kohaku, and engages Sesshomaru in combat only to have his borrowed body destroyed. Magatsuhi is later in its true form inside the Shikon Jewel locked in eternal combat with Midoriko, revealing to InuYasha that when Kagome makes a selfish wish on the Shikon Jewel, she will take Midoriko's place, with Naraku's soul replacing Magatsuhi thus allowing Magatsuhi to finally escape from its imprisonment. But in the end he and Naraku were destroyed forever by Inuyasha when he cuts the point of light in the darkness inside the Shikon no Tama with the Meidou Zangetsuha and arrives in the meidou outside the jewel to save Kagome. Afterwards, Kagome's selfless wish dissolved the rest of the jewel.
 * Magatsuhi

Foil to Inuyasha
Naraku is naturally all aspects, a foil to Inuyasha. Both of them are half-demons that sought to become full demons, but Inuyasha ultimately abandoned that goal when he found being a full demon, because losing his human side meant losing his human feelings. In a contrast, Naraku welcomed losing his human feelings, having always despised them.

Quotes
"Help each other and think of each other... then... because of that... end up dying."

"How touching... betraying your companions for your little brother's sake."

"I must separate her from Inuyasha... or it might mean my life."

"Resentment... for humans... and for the world."

"Jealousy? Is this, too, part of Onigumo's grubby heart?"

"Your time has come Kikyo. Now, Naraku returns you to the underworld forevermore."

"I am not going to kill you... I am going to break you."

"Foolish creature... it never realized that it was being consumed from within..."

"Kikyo, even after death, you..."

"Fools. Do they pity Kanna? But Kanna cannot feel a thing, be it pain, fear or sorrow. She cannot even understand the reason for your pity."

"My actual wish, you say? That's right. All I wanted... was Kikyo's heart. It looks like I won't even be able to... join her in death either."

Trivia

 * Naraku's "true form" (a giant horned spider) has appeared twice in the series.
 * This form also looks like the same yokai spider that transformed Onigumo into Naraku.
 * In a certain flashback, it is revealed that Naraku had the spider mark on his back prior to being burned.