Kadaunar Shrine is in the South Eldin Sky Archipelago, which can be reached by using the Eldin Canyon Skyview Tower.
Shrine Location
Kadaunar Shrine is at 1882, 1202, 1251 in the South Eldin Sky Archipelago, which can be reached by using the Eldin Canyon Skyview Tower. Use mine carts and Ascend to reach the part of the archipelago with the shrine.
Water Makes a Way
Up ahead, water is pouring into an enclosure in the lava. This has created a platform from the cooled lava. Use Ultrahand to pick up one of these lava platforms and move it out of the enclosure, then when the water creates more lava platforms, attach them to the first one until you have created a bridge of at least four platforms. Place it as a bridge over the lava. Walk across the cooled lava bridge to reach the other side.
Then take the bridge that you created and lean it against the ledge on the left that has a treasure chest on it. Go up the ramp of cooled lava and open the chest to get a random Construct Bow.
Next, go to the cracked stone wall and use a heavy weapon (such as the Rusty Claymore next to the wall, fused to a lava platform) to break it.
Beyond the stone wall, there is some flowing lava. Hit a hydrant to activate it, then use Ultrahand to hold the hydrant near the end of the shrine. Create a lava platform near the shrine with the hydrant, then bring the hydrant back toward you and set it aside where it won't create more platforms. Then wait for a lava platform to get close enough to jump onto, and use Recall on the platform to make it go back toward the end of the shrine. Jump from it to the end of the shrine, and check on the dragon ring to get a Light of Blessing and complete the shrine.