Infant

The  is Naraku's heart and seventh detachment. Despite his appearance, he is able to speak fluently. The Infant's main power is controlling people through the darkness in their hearts.

In the Story
Born in Mount Hakurei, the Infant was created to serve as the vessel for Naraku's heart while the human spirit of Onigumo was left behind as lumps of flesh. Naraku purposely created the Infant as such because he knew his heart would eventually betray him.

Entrusted to Kagura, the Infant left Mount Hakurei; he informed her not to attack Kikyō as she was not the one to kill her. When Kagura was resting from her trip, he informed her that Naraku had succeeded in killing Kikyō.

First Mission
The Infant later took control of the Lady of a mansion, ordering her soldiers to capture suspicious travelers in the area; it was all part of his mission to take control of Kagome for her ability to see the jewel shards. To ensure Inuyasha wouldn't trouble him, the Infant had Kagura use her Dance of the Dead to make a dead priest give a false story about Kikyō's whereabouts. Once she was captured, he tried finding darkness in Kagome's heart, but was surprised by how pure it was; there had to be some negative feeling inside. The Infant soon discovered Kagome's jealousy towards Kikyō and successfully put her under his control. When they attempted to place a defiled shard in Kagome to permanently put her under his control, the Infant found Kagome was resisting his manipulation; she accepted her jealousy as proof she loved Inuyasha. Inuyasha arrived and rescued Kagome; the Infant told Inuyasha that so long as he harbored feelings for Kikyō, Kagome could still be manipulated. Being taken away, the Infant decided to sleep, having used up too much energy trying to control Kagome.

Second Mission
When Naraku learned from Mimisenri that the final Shikon Jewel Shard was in the border to the world of the dead, the Infant was taken by Kagura to temples inhabited by powerful priests. The plan was to kill the priests and read their souls as they departed from this world to find a way to reach the border without having to die. Confronting a priest that appeared to be more powerful than the others due to detecting his and Kagura's arrival, the Infant succeeded in having him fatally wounded. Glancing into the priest's soul, he saw a land shrouded in white mist; however, at that moment, he was split in two by the last of the priest's power. Kagura took his halves to Kanna, who took the left half. The Infant regrew his right half while the original right half of his body grew into Hakudōshi, who continued his mission to find a way to the borderland. His being split into two different beings was all part of Naraku's plan; now Hakudōshi could take attention away from the Infant, effectively keeping Naraku's heart safe from his enemies.

In Hiding
The Infant was entrusted to Kanna and Kohaku for care; they took him to a castle where a Lady had just had a still-born child; Kanna sucked out the souls of all the attendants to make the claim that the Infant was her child more real. He slept most of the time, effectively keeping the ruse from being discovered. However, Princess Abi attacked the castle, correctly believing it to have a connection to Naraku. The Infant was protected by his foster mother and the castle staff; however, Kohaku killed the staff under Naraku's orders to retrieve him. Kanna sucked out the Lady's soul and took him back.

Kikyō's shikigami came dangerously close to finding him, but Naraku appeared before her and served as a temporary distraction. Naraku gives the Fuyōheki to the Infant, having stolen it from Gakusanjin; it would act as a sort of armor by masking his demonic energy. At this time, he conceived an even more brilliant idea for protection; having Hakudōshi created a demonic golem to house him. This lead to the creation of Mōryōmaru. When Inuyasha's group had the crystals of Gakusanjin's demonic energy, which could lead them to him, the Infant had Hakudōshi steal them. Mōryōmaru is then left for him to use as he pleases.

To strengthen Mōryomaru, the Infant has it attack the priest Goryōmaru to increase its powers by absorbing him; however, Mōryōmaru ended up being sealed by Goryōmaru and taking the place of the priest's devoured right arm. Hakudōshi later decapitates Goryōmaru, allowing Mōryōmaru to escape the seal and eat the priest. Hakudōshi takes him and Kanna to the stone ogre cliff, serving as bait for Kagura to lead Inuyasha's group into a trap.

Kikyō later comes across the Infant and Kanna while traveling, having been tracking Mōryōmaru's demonic aura. He and Kanna jump off a cliff to evade her, having Mōryōmaru fly them to safety.

Betraying Naraku
Realizing that Naraku is nothing more than an empty shell without his heart, which he has in him, the Infant decides to take Naraku's place with Hakudōshi's assistance. However, sometime after he is placed in Mōryōmaru by Kanna, Naraku locks him up with Mōryōmaru in the Goryōmaru's form; the statues from Goryōmaru's temple keep him sealed behind a barrier. Kagura is ordered to guard him, but Naraku doesn't let her know the Infant is inside Goryōmaru. Naraku continuously sends captured demons to the Infant's armor in order to strengthen it. He and Hakudōshi manage to persuade Kagura to release him with the promise of returning her heart to her right before Naraku's destruction. The Infant reveals his armor's true form and gives her Goryo urns to use bandits as a distraction to keep Inuyasha's group busy. Knowing that he needs Mōryōmarau to become more powerful if he is to try to replace Naraku, the Infant has Hakudōshi and Kagura attack Inuyasha's group and Kohaku for their shards. However, he is only able to get the one from Inuyasha's group; trying to take Kohaku's shard, he reveals that the boy has gotten his memory back.

When Hakudōshi is sucked into the Wind Tunnel, the Infant shows no remorse for the loss of his twin. Losing Hakudōshi and Kagura (who betrayed both them and Naraku, only to die from Naraku's shōki) left the Infant on his own; without assistance from others, he had to rely solely on strengthening Mōryōmaru to continue his plan to take Naraku's place.

Strengthening his Armor
The Infant sends out pieces of Mōryōmaru to find demons with abilities that hold potential for making Mōryōmaru stronger. A venomous demon ate a piece of Mōryōmaru's flesh, growing in size and power; however, Inuyasha slew it before Mōryōmaru could absorb it. An arm of Mōryōmaru ate members of a snake demon tribe, gaining their venom. Wanting to strengthen Mōryōmaru's resistance to attacks, the Infant revives the aquatic demon, Meiōjū, allowing him to regain the piece of his armor, which is the hardest amongst demons, to bring it back to full strength. He also uses Meiōju as bait to also take the Diamond Spears from Tessaiga. Once he has all these parts, the Infant transforms Mōryōmaru into a much more powerful form. He makes the poor choice of insulting Kagura in front of Sesshōmaru, who succeeds in cracking Meiōjū's shell with Tōkijin at the cost of the sword breaking.

Kanna later finds him, claiming to have defected from Naraku. Surprised, the Infant decides to read her so-called "heart" to see if she's being truthful. She tells him of twin demons (Kinka and Ginka) whose blood can strengthen Meiōjū's shell; though the Infant succeeds in taking in one of the twins and successfully gives Mōryōmaru a stronger shell, Tessaiga absorbs the other and gains the ability to resonate the powers of the twins, breaking the shell. Exposed to his enemy, the Infant quickly releases a miasma to make his escape.

He also had Mōryōmaru eat a moth demon sent out by Byakuya of the Dreams, taking a Shikon Jewel Shard from the young wolf demon Kai; however, he failed to get Kōga's.

Death
The Infant decided to confront Naraku, hoping to take his Shikon Jewel Shards. Naraku laughed at him for becoming a fat king inside his "castle" - Mōryōmaru. The Infant succeeded in reducing Naraku to scraps of flesh that covered Mōryōmaru; Naraku believed he was going to absorb Mōryōmaru with the Infant, but he turned the tables on him by absorbing Naraku into Mōryōmaru. He next proceeded to fight Inuyasha and Kōga, succeeding in capturing Kōga in Mōryōmaru's diamonds. However, much to his horror, the Infant discovered that Naraku was still alive and eating his armor from the inside-out. Trying to leaving, the Infant was stopped by Naraku, who had eaten the barrier-piercing demon tree Yomeiju; he was willing to die if it meant taking Naraku with him. However, Naraku fully absorbed Mōryōmaru, keeping the Infant trapped with Yomeiju's vines. Almost sucked into the Wind Tunnel like Hakudōshi had been, the Infant lost the Fuyōheki, leaving Naraku unable to mask his demonic aura.

By the time Naraku returned to Mount Hakurei to absorb Onigumo's spirit back into his being, the Infant had been completely reabsorbed.

Personality
Usually, the Infant is calm. Being born of Naraku's heart, he knows full well how negative emotions can influence others, believing that the desire to kill is contagious; the Infant believed Sango and Miroku would kill the guards simply because he ordered their deaths. He takes delight in toying with others' emotions; he taunted Inuyasha by saying Kagome's jealously towards Kikyō can still be used to his advantage. Like Naraku, he feels no remorse for any of his actions. As he is Naraku's heart, the Infant eventually sought to usurp him. When faced with the threat of being absorbed back into Naraku, the Infant was willing to die at Inuyasha's hands, showing he wished to have his own freedom, just like Kagura.

Appearance
As his name says, the Infant takes the form of a young baby. He has light violet hair that matches his eyes; however, his eyes lack pupils. Originally, he was wrapped in what would appear to be Naraku's baboon pelt. However, he later gains a green kimono and a light blue blanket.



Abilities

 * Manipulation:  The Infant had the ability to search deep within a person's heart for darkness and if they didn't have enough willpower to resist him, they would be under his control.
 * Barrier Erecting:  The Infant was able to erect strong barriers (like his master, Naraku) to defend himself. Unlike Hakudōshi, this barrier is controlled by himself and not Naraku which the reason why Naraku has to obtain the power of Yomeiju to penetrated it.
 * Shōki: After Inuyasha breaks Mōryōmaru's shell and he is rendered visible, the Infant released shōki to make Inuyasha back off and to make his escape. He only used this once, so it's unknown how potent his shōki is.

Trivia

 * Many English-speaking fans consider the Infant's true name to be, which is how other characters refer to the Infant in the original Japanese language version. However, akago is merely a Japanese word for infant, and is not really a name.
 * Interestingly, the Infant never speaks in the series after being split in half until after Hakudōshi dies.