Kohaku (琥珀, こはく, Amber) is Sango's younger brother. He is also a yōkai Taijiya, like his sister and father, from the Village of Demon Slayers. He was manipulated by Naraku through most of the series, kept alive only by the Shikon Jewel shard in the back of his neck.
During the storyEdit
He was killed by a demon posing to be a castle's lord during one of the Demon Slayers' missions and was made to kill every Demon Slayer that was there. He is later revived by Naraku as a human puppet and has a Jewel of Four Soulsshard embedded in his back to keep him alive and under the control of Naraku without memory of what he had done. But recently, Kohaku has somehow got his memory back and still takes orders from Naraku to get to Naraku's heart. Kohaku, at first before being slain, was inexperienced with his weapon, a kusarigama (a sharp sickle on a chain). He then becomes a rather advanced wielder with the power of the Shikon Jewel shard. he met his sister for sometimes at first he cannot remember her and tried to kill Kagome under Naraku's mind.
After Kagura dies, he hopes that he can find redemption for himself by traveling with Kikyo, and remains by her side until she tells him he must leave her to keep his shard pure. Saved from Byakuya by the timely arrival of Sesshomaru, Kohaku forms a friendship with Rin and helps to protect her. In chapter 539, Kohaku's jewel shard was removed but surprisingly, he did not die or wither away. This was due to Kikyo's light releasing the jewel shard and remaining in Kohaku's body, as explained by Kagome.
In the last chapter, Kōhaku goes with Kirara and a new demon-slaying weapon which Totosai made for him, so he leaves and becomes a demon slayer that helps people. When Totosai asks him if he will visit his sister Sango, he replies that he will not, since the house is getting too crowded.
Kohaku is a humble and kind-hearted boy who cares for his family and is very close to his sister Sango. When Naraku controlled his mind he was forced to kill everybody including his own father, leaving him in a slight state of shock. Early on Naraku used Kohaku not wanting to remember as a way to keep control over him. However, when his memories returned on their own, he did not seemed to be affected as severely as before.
- The new Kusarigama that Kohaku received from Totosai is extremely reminiscent of the corrupted weapon that he had as Magatsuhi's body.
- As stated by Sesshōmaru's mother, Kohaku can't be revived by Tenseiga because his life has already been unnaturally prolonged.