Nikosen is the 412th chapter of the InuYasha manga.
Inuyasha and group come across some villages who mention a wilted forest, destroyed by a demon's venom. The villagers say it was the work of Nikosen. The group investigates, and finds tree roots that are so fragile they crumble to dust at the touch. Miroku says that the villagers said Nikosen devours the vital sap of all trees, and that the demon was a hermit sage long ago. Kagome says she didn't realize a sage could turn Demon, and Sango says it isn't uncommon. Kagome then senses the presence of a tainted Shikon Jewel Shard. Miroku asks Inuyasha if he can follow Nikosen's scent, but he hesitates and instead asks Kagome to lead them with the presence of the shard. She protests because the night of the new moon is coming, and Inuyasha will soon lose all his demonic powers.
Shippō smirks and comments that Inuyasha's sense of smell must be significantly weaker if he wants Kagome to lead the way instead of following his nose. The group decides to rest for the evening and pursue Nikosen tomorrow when Inuyasha will be at full power again. Sango wonders what Naraku is up to, giving out another shard like this.
Suddenly, Nikosen appears and Kagome notices he has the Shikon shard embedded in his mouth. The demon asks if they came to slay him. Inuyasha responds with his own question, asking if Nikosen is working with Naraku. Nikosen says "A fellow by that name gave me a Shikon shard and warned me that a fool with a scaled-blade would hunt me down. He told me if I fell to him, it would be my own hard luck, but if I slew him, the shard would be mine to keep! Inuyasha draws Tessaiga about to attack, but the blade reverts to its rusty katana state; Kagome realizes this is because night is falling. Nikosen spews poison at Inuyasha and the hanyō falls off of a cliff.
Sango uses her Hiraikotsu to cut off Nikosen's head, but the head continues talking and laughs as Kagome calls down to Inuyasha frantically. Kagome says Nikosen must still be alive after being beheaded because of the Shikon shard. Miroku and Sango chase after Nikosen's head while Kagome and Shippō go down to help a now Human Inuyasha. Inuyasha gets angry that Naraku sicced Nikosen on him just to get him to use the dragon-scaled Tessaiga. Kagome realizes Byakuya must have told Naraku that Inuyasha hasn't mastered the technique yet.
Nikosen's nearby headless body begins to rumble and then sprouts a new head, to everyone's surprise.
Characters in Order of Appearance