Etymology of terms.

[Cilia]

Many thanks to those who provided additional info. It's not that I didn't know or couldn't be bothered to look it up, but just wanted to keep things pretty concise since I tend to infodump. (Also Bahamut does owe his modern depiction as a dragon to D&D, but he is the platinum dragon god of the good metallic dragons. Likewise Tiamat owes her modern depiction as a dragon to D&D, where she is portrayed as a five-headed evil dragon goddess, with one head representing each variety of chromatic dragon - red, blue, green, black, and white.)

Enough showing off my nerdiness. A few more things:

Hecatoncheires: three giants from Greek mythology stated to have a hundred hands and fifty heads. Sealed in Tartarus until Zeus freed them to help with the Titanomachy, after which they became the guards of Tartarus. Among their number were Kottos and Gyges, the two hecatoncheir bosses in Copperbell Mines. The third named hecatoncheir, Ouranos (final boss of Copperbell HM), is another name for Uranus, Greek god of the sky and, as in-game, father of the hecatoncheires (but not one of them himself).

Vidofnir: a rooster said to sit atop Mimameior, a tree similar to Yggdrasill, in Norse myth.

Vedrfolnir: a hawk said to sit between the eyes of the nameless eagle perched atop Yggdrasill.

Vishap: a dragon from Armenian mythology, said to live on Mt. Ararat.

Rangda: demon queen of the Leyaks, floating heads with entrails hanging out behind them, in Balinese mythology. Opposed by Barong.

Gyascutus: a mythical beast with longer legs on one side for traversing hills, also known as "sidehill gougers." Also a genus of beetle.

Macuahuitl: a weapon traditionally from Mesoamerica before the European conquest of the continent. A wooden sword using embedded obsidian shards to create a blade keener than steel.

Irminsul: a sacred, pillar-like object in Saxon pagan religion. Its exact purpose remains unknown.