Poison is Also Medicine

Collect 10 stems of Emerald Arrowhead and 10 Kurru Berries on the Green Cape and return to Whew Black-Feather in the Glittering Wing village.

I've heard you want to receive wings, wingless one. Then you will become a swore brother to People of the Wind! From then on, you will be called Son of the Wind. A son always helps his father, does not he? Then you will help us!
Father of People of the Heavens, Karrok Stout-Hearted, is wise and strong, but he's ill. Very ill. When we fought with the damned red rebels, Karrok flew in the vanguard! He led our tribe in battle! An arrow hit him right in chest. Now Karrok is really sick. Between life and death. And a new Son of the Wind can help me cure him.
Go into forest to find kurru berries and emerald arrowhead. Kurru berries are very poisonous. You can die if you swallow even one. Arrowhead is useful and medicinal. It treats wounds, cough, and infertility. It treats everything! Combined together, they are strong enough even to resurrect a corpse.

Gather berries carefully. Juice is also poisonous. If you burn yourself with juice, apply an arrowhead right away. It will extract poison and save you.

You've done a great job. You've found juicy berries and the emerald arrowhead. Thank you, Son of the Wind!