Although not appear as one of the summons in Final Fantasy series but Tiamat often appear as boss monster that must beaten in almost all Final Fantasy series. In Final Fantasy series Tiamat often appear in dragon shaped creature but let's see what the myth tells about it.
The history of Tiamat was the protagonist is one that has most interested one, because in all Final Fantasy series Tiamat appear always as a Antagonist character. The myth itself deals with the creation of the world according to Babylon myth. According to them, before the creation of the world, there is only two gods: Tiamat and Apsu (female and male respectively), who had several children called giants. They decided to battle against their parents because win in numerical (almost same like the Greek myths, which there is a rebellion of this style). The Giants managed to defeat Apsu, his father, before he could react. When Tiamat know this her fury was grew beyond the known, and in her madness decided to create all sorts of creatures and monsters to stop her children .
The last giant who surviving which is most courageous among them, Marduk. In the final battle Marduk beat his mother and departed her in two. With the top half of Tiamat's body formed the sky and the lower part formed the earth below. Since then according to the Babylonian, the Giants belief live in the sky.