Ok, commenting while I'm watching:
Tiamat: According to Sumerian Mythology, Tiamat (translated as the Salt-Water Ocean) wasn't, as they're claiming, a planet, but actually, along with her Consort, Apsu (the Sweet-Water Ocean), were the two original Gods. They thought to be the embodiement of the Tigris and the Euprhates, and the place where the two met was how the world began. The place where they met became the birth of second pair of Gods, Lahmu and Lahamu (translated as the silt deposited at the bottom of the ocean). From there, came the rest of the Gods.
The destruction of Tiamat is recorded as being brought about by Marduk, another God. He threw a net around her, and when she openend her mouth to swallow him, he pierced her heart with a bow, and then cut her in half, placing half of her above the world to create the sky. With the other half, he built a temple to the Gods.