Tsunamjin

Tsunamjin is an enigmatic figure whose name keeps appearing as the group investigates the villain Mujina. They are believed to be a gold dragon.
Tera has been told by her deva Azume that Tsunamjin had a hand in 'nudging' all members of the party to be in the same place at the same time, though it is unknown how they accomplished this, or for what purpose.
It is known that almost a thousand years ago Tsunamjin united the formerly warring Houses off against a nameless calamity, and likely was the one who struck its name from history. The census records of the period attributed countless deaths to 'starvation' and 'hunger'. There was at least one year from then in which the number of births was exactly equal to the number of deaths, and the number of deaths then began outweighing the number of births.
From speaking with a devil contractor, the group learned that Tsunamjin struck a deal with the denizens of the Nine Hells to imprison the Hunger in the Abyss, with the help of an unknown tiefling called Trickery. When the party visited the shattered Feywild, they also learned that Tsunamjin enlisted or possibly conscripted the fey lords into 'The Great Duty' which seemed to involve keeping the Hunger imprisoned. To do this, the Feywild was merged with the Abyss.
Azume mentioned that Tsunamjin then went into isolation a long time ago because it 'did not wish to become a tyrant'. Tsunamjin is thought to still be alive and in hiding somewhere in Thousand.
Tsunamjin approached Tera in a dream and answered a few questions about himself and the Hunger. There Tera learned that Tsunamjin was essentially a gold dragon, but one that was created specifically to defeat the Hunger. He is not a god in the truest sense, but may as well be considered one from the world-altering power he seems to wield. His intentions seem so far benevolent, but he has gone to some particularly extreme lengths to keep the Hunger at bay.