This page explains how to find the Daag Chokah shrine.
How to Find the Shrine
The Stealth armor set that you can buy in Kakariko could be helpful for finding this shrine.
Go to Keo Ruug Shrine to reach the Korok Forest. Go west from the Master Sword pedestal and follow the bean lamps. Talk to Tasho the Korok. Tasho asks you to follow Oaki.
Follow Oaki. After walking between two bushes, Oaki will stop and say "what was that?" Then Oaki will turn left. After a moment, Oaki will say "Everything is A-OK!" and start running. After Oaki turns right, he will stop and say "I remember this tree!"
Then he will go around a corner and will stop a moment to say "This is the right way..." while looking around. Then he will continue on. A couple of tree branches will fall, startling Oaki. He will go to look at one of the tree branches, so you might want to crouch in the tall grass to avoid being seen.
When Oaki starts walking away again, you can follow. Oaki will go forward to a hollow log with flowers in front. He will stop and look around at the flowers (and will turn around and look in your direction), so crouch down to avoid being seen.
Then Oaki will start walking and say "Halfway there!" He will go through the hollow log. Don't follow too closely, because Oaki will turn around at the end of the log, and will see you if you are close by. You can walk alongside the hollow log to better avoid being seen.
After Oaki goes past the end of the log, go into the end of the log while keeping an eye on him. He will say "Is... is someone there?" then will soon say "Ah! A ghost!" and will turn around and start running the way he came. You can hide in the end of the hollow log, because he won't go that far. Then he will start walking away again and say "It was just a shadow".
After a while, Oaki says "This isn't so bad. I'm not scared one bit." and starts running. Then he stops and says "OK, I'm a little bit scared."
Farther ahead, a wolf will appear. Oaki will turn around to run away from it, so hide behind something. If possible, shoot it with your bow (it will stay dead if Oaki sees you and you have to start over), then stay hidden, because Oaki might come back to investigate, or walk toward you after running away. When the coast is clear, follow Oaki again.
At this point, just follow at a distance until he says "Woo! I've finally made it!" and starts dancing and spinning around. After that, it's OK if Oaki sees you. Just walk up to Oaki to finish the trial.
Treasure Chest in the Shrine
The chest in the shrine contains an Ancient Core.