13.1 Catching a Reekfish
After getting the first Mirror Shard from Arbiter’s Grounds return to Zora’s Domain. Find a tunnel in the lower area that was previously blocked by ice. It leads to Snowpeak. At the bottom of the mountain you will meet Ashei, who gives you a sketch she has drawn of the Beast of Snowpeak holding a Reekfish. You cannot climb to the top without getting lost in the blizzard, so leave the area for now.
Travel to Kakariko Village and go to the area behind the Graveyard where you got the Zora Armor. You will find Prince Ralis. Show him Ashei’s Sketch and he will give you his Coral Earring to use as a fishing hook. Ashei’s Sketch will be removed from your inventory.
Return to Zora’s Domain and fish by the Mother and Child rocks (opposite the path to Snowpeak). Catch one of the Reekfish with the upgraded Fishing Rod and transform into Wolf Link. Examine the fish to learn the Reekfish Scent. As expected, it leads to Snowpeak.
13.2 Meet Yeto
Go down the tunnel to Snowpeak, cross the ice and use your senses to follow the Reekfish Scent through the snowstorm. At one point you will lose the scent: go right and follow the path until you find it again. Shortly afterward you will reach a dead end: charge into the wall to knock down some snow and run up it.
The scent eventually leads to cliff face, where it disappears. Use your senses to find a digging spot in the snow. Dig down and you will emerge inside a cave. Climb up the vines until you reach a stone door and exit the cave.
Defeat the Shadow Beasts that drop from the Portal and talk to the Beast of Snowpeak – called Yeto – to learn the whereabouts of the next Mirror Shard. Roll into the tree to knock down a frozen leaf and use it as a snowboard to slide down the mountain. At the bottom you will find the area’s dungeon, the Snowpeak Ruins.