Saint Seiya: Meio Hades Elysion-hen

After the 12 Gold Saints sacrifice their lives to destroy the Wailing Wall, The Bronze Saints enter the deepest realm of the Underworld, Elysion, where they face off aganist Hades`s two most powerful servants: The Twin Gods, Hypnos and Thanatos, before they can reach Hades for the final battle.

(summary from ANIDB)

6 OVA episodes
New series to be released March '08.
See also: Saint Seiya: The Lost Canvas - Meiou Shinwa