Batrachi

The batrachi, also called amphibioids, were an ancient amphibious race that were counted as one of the Creator Races native to the worldl, who dominated the supercontinent of of the south.
This amphibious race evolved in the seas, their growth mirroring the sarrukh on land. When they became amphibious, they moved onto the land and supplanted the sarrukh
The Batrachi Empires rose to power in the vaccume of the Sarrukh Empire. They out-competed the rising power of the yuan-ti, ensuring they would never achieve the heights of their creators, the sarrukh.
The batrachi grew to the height of their power under the wise leadership of Zhoukoudien, the High One. However, their golden age ended abruptly when the High One was killed in battle by Omo, a titan thane of the Jotunbrud Tribes, The batrachi lord Bazim-Gorag later called Zhoukoudien a fool who unwisely made war against the Jotunbrud and lost the empire.
The batrachi were losing a war against the titans. In their desperation, the batrachi enacted a great summoning ritual that unleashed several once-imprisoned primordials. The gods swiftly opposed the primordials. The primordial Asgorath, the World Shaper, even hurled an ice moon or comet at the planet, in order to destroy what she could not have, in an event called the Tearfall. Disastrous earthquakes, fires, and windstorms swept across all the land, erasing whole continents and rearranging the seas. Ancient sarrukh legends made cryptic mention of the "changing of the stars".
The extreme climate change swiftly led to the end of batrachi civilization. After a cold period called the seven-turn winter, many batrachi—among them Bazim-Gorag—left Toril for the plane of Limbo. There, the batrachi were changed, for at least the second time in their history, by their god Ramenos to serve his agenda. They created what became known as the Supreme Throne as their kingdom.