Arbiter's Grounds (Dungeon)

The Arbiter's Grounds is the fourth dungeon in Twilight Princess, located at the far end of the Gerudo Desert. The Arbiter's Grounds was a prison built to house the most ruthless criminals while they awaited trial, execution, or exile to the nether realm of the Twilight. The Mirror Chamber, home of an ancient relic known as the Mirror of Twilight, stands atop the ruins of Arbiter's Grounds, where the sacred council of the Sages presides over the cursed grounds, conducting trials and executions of convicted criminals. Its appearance from afar resembles the Roman Colosseum, but inside it resembles an Egyptian tomb.

Dungeon
The Arbiter's Grounds contain four floors and two basements. The first section of this temple is very similar to the Forest Temple in Ocarina of Time, as it requires tracking down and destroying four special Poes in order to light four special torches and proceed into the inner sanctums of the prison. Link can become a wolf so that he can follow the scent of the Poes' essence, which helps him to seek them out and destroy each. After destroying each Poe, one of the four torches in the main room will be lit; once all four torches are lit, a door leading deeper into the prison will open and Link will be able to advance to the second part of the dungeon, where new and different types of obstacles await him, including metallic rails that give Link a ride if he has an ancient device known as the Spinner.

The Arbiter's Grounds teems with the undead. Its halls are haunted by vengeful wraiths, from Stalfos and Stalkin to ReDead Knights and Bubbles, and even the occasional pack of Ghoul Rats. Also, Link encounters swarms of Poison Mites, which behave in a somewhat similar fashion to Morths, and can be dispatched in the same way using the Spin Attack, or kept at bay by the light of a Lantern. The item obtained in this temple is the Spinner, an ancient device that can be used to ride along rails to access hard-to-reach areas, as well as spin large gears to move walls and reveal hidden pathways. Link obtains this after defeating the dungeon's mini-boss, Death Sword, a vengeful demon that haunts the sword it once wielded in life, in the basement of the dungeon.

Deep within the Arbiter's Grounds lay the remains of a fierce beast, the dungeon's boss, Stallord. Its skeleton is reanimated when Zant appears and stabs the Twilight Sword through the creature's skull. Link is able to defeat it largely using a combination of the Spinner and the Master Sword. After clearing the dungeon, Link will be able to progress to the Mirror Chamber, where the Mirror of Twilight is found.

Theory
While it is not certain, there is a possibility the Arbiter's Grounds and the Spirit Temple from Ocarina of Time are the one and same due to their locations at the far end of the Gerudo Desert, the presence of the Gerudo Goddess of the Sand, and the Spirit Temple's theme of mirrors (the Arbiter's Grounds was most famous for housing a particular mirror, the Mirror of Twilight). The large round mirror that allows Link access to Twinrova's chamber in Ocarina of Time looks very much like the Mirror of Twilight, and its central location and role of granting Link access to the temple's boss give this particular mirror significance in the completion of the Spirit Temple. If this mirror was in fact the Mirror of Twilight, it would further support the theory that both places are the one and same.

Trivia

 * Besides the Imp Poe in Jovani's House, the four sub-boss Poes are the only ones that must be defeated in order to proceed in the game.
 * Each Sage residing in the Mirror Chamber corresponds to a Sage from Ocarina of Time regarding their emblems, representing the six medallions that need to be retrieved in that game, except for the Medallion of the Water Sage, whom Ganondorf had slain with the Sword of the Sages.
 * Throughout the dungeon, images of the Triforce can be seen in places such as above the door closed by the four Poes.
 * Throughout the dungeon pictographs can be found, some depicting Stallord and others of a warrior.
 * Four of the Sage Medallion symbols, Water, Spirit, Fire, and Light, are inscribed above the doorways in Arbiter's Grounds. It is unknown why the Forest and Shadow symbols are missing.
 * A picture of Arbiter's Grounds can be found in the Snowpeak Ruins, in the room Yeta is sitting in.
 * Arbiter's Grounds is the only dungeon in the game (besides Hyrule Castle) where Midna does not create an exit portal after the boss is defeated.