Tiamat

Notes:
 * Spawns around E-9 every 3-5 days.
 * Around 100,000HP.
 * Killable by: 18 characters level 75 + a party for Adds, or 11 well prepared level 75 characters.
 * Recommended to cast offensive Water and Thunder spells by Black Mages when Tiamat is in flight.
 * Special Attacks: Draw In, Mighty Strikes (multiple times), Auto-Regen (low), Blaze Spikes, and Firaga III.
 * Tiamat uses the wing attack Tebbad Wing which afflicts anyone hit with Plague.
 * Tiamat gains a large, undispellable attack boost when health is under 25%.
 * Tiamat's Horrid Roar dispels all buffs including food and resets hate.
 * Tiamat's Wing abilities can be blocked by terrain differences.
 * Tiamat lands for 2 minutes and then flies for 2 minutes.
 * Tiamat's air attacks are fire based. Because of this, it is recommended that your tanks have fire resist sets.
 * There are many aggressive monsters in the area, including Cave Antlion, Air Elemental, Earth Elemental, and Arch Corse. It is recommended to have an outside party defeat these.

Historical Background
In Mesopotamian mythology, Tiamat (Tiamat [Babylonian], Tamtu [Sumerian]) is a giant female dragon which was the primordial creatrix of all existence. She created the world and the gods, though this world had no land and was a vast water-world, filled with the waters of chaos. Tiamat personified the saltwater (ocean) while her consort Apsu (Apsu [Babylonian], Abzu [Sumerian]) personified the 'sweetwater' (freshwater). The intermingling of these two waters created the gods. In the Enuma Elish (Mesopotamian creation epic), the gods bother Tiamat & Apsu, so the two decide to kill all their children. The god Ea discovers their plan and pre-emptively slays Apsu or casts a spell that puts him in a death-like sleep (since the waters of Apsu still exist even after his 'death'). Tiamat then sought revenge by creating an army of monsters and a new consort, Kingu (alt. Qingu) to be their general. Tiamat was slain by Marduk who trapped her with a "net of winds", shot arrows down her throat, and then cleaved her body in two, with the upper half creating the heavens and the sky and the lower half creating the earth. Tiamat is Akkadian for "sea".

Dungeons & Dragons (one of the inspirations for the original Final Fantasy) used Tiamat as a monster, specifically a 5-headed dragon (one black, one red, one green, one white, one blue). This is likely where Square got the idea to place her in Final Fantasy I.