The Soul Shrine (魂のほこら, Tamashii no Hokora?) is a bonus dungeon in the Advance version of Final Fantasy VI. The shrine becomes available after the Dragons' Den and the main story have been completed. It is located on a small island near Mobliz.
The Soul Shrine contains a series of 128 battles against most of the enemies and bosses, including the new dragons from the Dragons' Den. While the battles are set up in a particular order (i.e. the Dragons' Den dragons are the last tier the player faces), there is a bit of randomness included with some enemies swapping levels. The player can also fight monsters missed during the initial playthrough, meaning there is a chance to get a 100% completed bestiary here. Leaving the shrine causes the battles to be reset.
Another important thing about the Soul Shrine is that the enemies drop items. This gives another chance to pick up some nice rewards, as well as the possibility of getting multiples of some of the ultra-powerful items. For example, Samurai Soul is in the Soul Shrine, which means the player can get as many Master's Scrolls as possible.
The Soul Shrine also includes a few new monsters called Glutturns. They appear asking for curative items, like Elixirs and Hi-Ethers and, if not fed, attack the party with some particularly devastating moves, including Ultima and Diabolic Whistle, among others. The real goal here though is to steal. Glutturns have useful rare steals, including Souls of Thamasa, Celestriads, Force Shields, and Master's Scrolls. They are the only source in the game of unlimited Souls of Thamasa.
Upon completing the challenge, the player is given the key item Master's Crown. Like other Final Fantasy arena items (i.e. Final Fantasy X's Mark of Conquest), it has no in-game purpose. Beating Soul Shrine several times does not give more Master's Crowns. It is possible to use this area to level up and gather up some rare items for use against the Omega Weapon.