Deku Seeds are one of the available collectibles in Cadence of Hyrule. But what do they do? How do you get them all? Well, given the semi-random nature of Cadence of Hyrule's
What Are Deku Seeds?
Deku Seeds are items obtained by defeating enemy Deku Scrubs throughout the world. Each one drops a seed, which you can take to Tingle in the Lost Woods. Tingle will give you an increased stamina bar at 10 seeds, and you'll unlock a new hidden playable character at 20. There appears to be slightly more than 20 seeds every playthrough--I believe I picked up 23 of them on my run.
So you have a little wiggle room for both the unlocks, but you'll need to be diligent regardless.
How do you Collect Deku Seeds?
You'll find almost all the Deku Scrubs on the main world map. They look a little like normal bushes, but they pop up and lob projectiles at you. You can reflect the projectile seeds back at them, or use something like a Bow to kill them before they go back underground.
Just knocking out the Deku Scrubs as you go will get you most of the way there, but you might find yourself a little short for unlocking the new character. In the Lost Woods, there's a cave to find (look for a bombable wall on the screen with ghosts) on which upon entering, you'll find eight Deku Scrubs to defeat and glean their seeds from. Helpful!