Ulria Grotto is a location in The Legend of Zelda: Breath of the Wild. It is located in southeastern portion of the Akkala Highlands region of Hyrule. It is southeast of Akkala Highlands Ukuku Plains and northeast of Zora's Domain as it is near the border that separates the Akkala and Lanayru provinces.
Ulria Grotto is a vast quarry-like grotto that contains many metallic Boulders and Ore Deposits. An Updraft concealed by rubble is located west of the Grotto's central pond which Link can use to get out should he fall in. Near the bridge leading to Davdi Island in the Lanayru Sea there is the remains of an potential mining cabin as a Iron Sledgehammer can be found there implying Ulria Grotto was mined at some point though it was not on the same scale as the industrial mines of Death Mountain and Eldin Canyon. Given its proximity to Zora's Domain and water at the bottom of the grotto presumably Zora may have mined the Grotto as Zora's Domain was constructed using Luminous Stones.
However the grotto conceals the hidden Ke'nai Shakah Shrine indicating the Sheikah may have mined the area in the past or the Royal Family of Hyrule had research teams excavate the area in search of the Shrine though presumably the Great Calamity prevented it from being discovered a century before Breath of the Wild as the modern day Shrine researcher Jerrin is apparently unaware of its existence. The Shrine is hidden inside a cave blocked off by Weak Walls of rubble. Link can break them using Bomb Arrows as long as it isn't raining though he can also break them with a properly timed aerial attack with any Goron Hammer sword, Drillshaft, or Iron Sledgehammer. Once an opening is created Link can access the Shrine. After its Travel Gate is activated the Ke'nai Shakah Shrine becomes a fast travel point for Ulria Grotto. However due to its close proximity to the East Reservoir Lake it experiences the torrential rain caused by Divine Beast Vah Ruta. However it is still possible to use Bomb Arrows to destroy the wall before taking on Vah Ruta by taking advantage of the little alcove that shelters the cave entrance from rain though Link should where strong armor to protect himself from damage caused by the Bomb Arrow's explosion should he inadvertently get caught in its blast range. Alternatively he can drop a Remote Bomb while Paragliding near the wall detonating it while it is still in range of the wall though again Link should wear strong armor to protect himself should he get caught in the bomb blast.
Besides these methods, there is a Boulder located directly across from the cave which Link can launch using the Stasis Rune to store kinetic energy to launch it towards the wall like a cannonball to destroy the wall. However Link only has one shot using said boulder (if he fails then he must leave the area for it to respawn) though he can substitute it with a metallic one as they are easy to move into position though Link can also use them to test fire before using the stone boulder. This is by far the safest method that can be employed before confronting Vah Ruta to put an end to the torrential rainfall.
Like many locations in Breath of the Wild, Ulria Grotto may be named after a character from a previous game, namely Ulrira.