The Lomei Labyrinth Island is a location in The Legend of Zelda: Breath of the Wild. It is also a mazed mini-dungeon located in the Akkala Sea region of the Akkala northeast province of Hyrule. It contains the Shrine quest "Trial of the Labyrinth" and houses the Tu Ka'loh Shrine at its center.
Link can encounter in this labyrinth Guardian Skywatchers, Stalkers, Decayed Guardians, Keese, Fire Chuchu, and Electric Chuchu. He can find several Treasure Chests containing equipment or gems. The island itself is apparently a man-made island presumably by the ancient Sheikah. Link can also find a Ancient Shaft, Ancient Cores, and Giant Ancient Cores in certain treasure chests hidden within the labyrinth. A Great Flameblade, Thunderstorm Rod, Soldier's Bow, and Soldier's Shield also spawn within the labyrinth. A Royal Bow spawns in the northwest corner of the labyrinth while a Royal Halberd spawns in the northeast corner of the labyrinth. A Royal Broadsword and Royal Shield spawn in a hidden passage in the northeast portion of the northern square that contains the Shrine. Accessible by climbing a set of walls near a long path that seems to dead-end at the southeastern corner of the northern square.
In certain dead-ends Link can find a piece of Yellow Chuchu Jelly that spawns within the labyrinth. The jelly is bait that leads Link into an ambush by an Electric Chuchu.
Underneath the Labyrinth is a large chamber full of derelict Guardians as well as aging Decayed Guardians and Guardian Stalkers. The Decayed Guardians are inactive and must be attacked before they activate and attack Link. The Guardian Stalkers activate as soon as Link approachs them. The Camera Rune can identify the Decayed Guardians and Guardian Stalkers from the derelict inoperable Guardians. In the middle of the chamber is a Treasure Chest containing a rare Diamond Circlet. This chamber can be accessed via climbing or falling down the shaft with the Updraft coming out of it in front of the Shrine. The Updraft can be used to exit the chamber via Paraglider.
"The Master Trials"
A new treasure chest appears inside the labyrinth upon "The Master Trials" DLC pack installation and after the side quest "EX Teleportation Rumors!" is triggered. It contains a new key item, the Travel Medallion, allowing Link to teleport from anywhere at a temporary quick travel point chosen on the map.