Hyperdimension

The Hyperdimension (超次元, Chō-jigen)  is a great space and time anomaly which divides the Underworld from Elysion. This void is only accessible once the  Wailing Wall situated behind the Throne of Hades in Judecca is destroyed.

This area extends for many light years and is a place where space and time are destroyed. Only the Gods or people who received their protection are able to cross the area without disintegrating immediately, subjected to great cosmic forces.

In the original manga, Seiya, Shun, Hyoga and Shiryu were able to cross the void and reach Elysion because their Bronze Cloths were soaked by the blood of Athena. Hades gave Pandora a special necklace that allows her cross the Hyperdimension, and in turn she gave this necklace to Ikki, who went through it following his companions. On the other hand, Griffon Minos, one of the Judges of Hell and one of the most powerful Specters, disintegrated when trying to cross the void wihout protection, and the same happened to Basilisk Sylphid.

Poseidon used his divine cosmo to send five Gold Cloths through the void to Elysion, in order to help the Saints fighting Hades.

In The Lost Canvas, it appears that Hades, Hypnos and Thanatos are able to open the Hyperdimension anywhere at will. Thanatos opened the Hyperdimension during the battle with Cancer Manigoldo and Cancer Sage, severing Manigoldo's leg. Manigoldo, however, used his "Seki Shiki" technique to drag Thanatos' human body into the void, destroying it at the cost of his own life.

Relationship with the River Lethe
When Charon speaks of Elysion, reveals that the place is on the other side of Lethe, Shaka with Athena explains that it was beyond the Lethe to search for Hades. Moreover, in the Divine Comedy, the stream is supposed to make you forget the sins of those who bathe in it. In Saint Seiya, the area between the underworld of Elysion plays a comparable role as "purified" it is not divine annihilation.

Appearances

 * Saint Seiya (debut)