King Jhil leads the people of the Valley of the Wind. He had eleven children, but Nausicaä was the only one who survived long enough to become his heir. Throughout his lifetime his health has deteriorated due to the proximity of the valley to the Sea of Corruption and its toxins. Due to his paralysis, he has to transfer most of his duties to Nausicaä.
Eventually, he has to send Nausicaä off to fight with the Torumekians, since he can no longer move. Jhil eventually dies, since his bones are ossifying from the miasma of the forest. His illness causes him to go blind shortly before his death  . He recognizes the message Mito brings him from Nausicaä about the Daikaisho  and agrees with the other chieftains that they must Break of the Periphery Treaty in order to survive a Dorok invasion  but orders Mito to find Master Yupa with the Valley Gunship in order to aid Nausicaä. After that, he dies and the Periphery chieftains and the people of the Valley of the Wind mourn his passing .
In the film Jhil has a similar role, but is eventually murdered by the Torumekians.
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