Ereshkigal

Notes:
 * Spawns around F-8.
 * This is a very rare NM. It is theorized that it only spawns in Dark or Double Dark weather. Many reports of spawns in different weather (confirmation needed).
 * De-spawns when Dark Weather is over unless engaged in combat.
 * Spawn time is 21-24 hours.
 * Has a permanent Endark attack that you cannot Dispel.
 * Killable by: 3 characters level 60+ (reported solo by DRG66/BLM18, BRD60/WHM30 and by 75BLM/37RDM).
 * Has approximately 3000HP.

Historical Background
In Mesopotamian mythology, Ereshkigal is the queen of the underworld, Irkalla. She is the sister of Ishtar. She ruled over Irkalla with Nergal (god of war & pestilence), though she was the top ruler in this realm of the dead. She is considered dark and violent. Ereshkigal translates as "lady of the great earth" or "lady of the great place".