Thassa's Influence

To most mortals, Thassa is the sea, and the sea is Thassa. The wind and waves, the tides, and the ocean's bounty, ranging from small fish to the enormous krakens—all these are Thassa's dominion. The sea has many metaphorical aspects that Thassa oversees as well: ancient knowledge, long-term change, introspection, voyaging, and repetitive patterns such as the tides.
Thassa governs the slow changes wrought by the passage of time, such as the weathering of rocks and the erosion of beaches. Where Nylea controls the eternal cycle of the seasons and Kruphix monitors the flow of time, Thassa holds sway over the slow-acting but irresistible forces that alter the world over hundreds or thousands of years.
Krakens and other behemoths of the deepest oceans move at Thassa's command. She is protective of what she calls the greatest of her children, and she usually keeps them out of harm's way in the darkest depths. A mighty kraken sighted close to shore is a sure sign of Thassa's displeasure.

Thassa's Goals

Thassa is never satisfied with the status quo, and she also never advocates hasty, uncontrolled change. She constantly resculpts the physical world, altering coastlines and upending familiar trade routes. There is no ultimate goal to this ongoing transformation; the purpose is change itself. Thassa believes that change is essential to existence, and she opposes anyone who tries to establish or maintain a permanent order to the universe. She aids and inspires forces of change, the rivers that wear down mountains and the tides that claim whole continents. She sometimes seems disinterested in the intrigues of the present, even in her own current schemes, as her thoughts drift toward what the future holds.

Divine Relationships

Thassa disdains the shortsightedness of her fellow gods, most of whom have convinced themselves that they can impose lasting order on the cosmos. At the same time, her realm is unassailable, and she believes that the changes she advocates are inevitable in the long term. So although Thassa frequently disagrees with the other gods, she doesn't fear them.

Heliod considers Thassa his favorite sibling, despite her unwillingness to agree with his plan for a permanent order. Thassa, who rules depths that have never seen the sun, considers most of Heliod's schemes pointless and opposes them if they seem to threaten harm.
Thassa took pity on Purphoros and aided him when Kruphix hobbled his mind, and Purphoros has not forgotten it. The two of them agree that old things must make way for new things, but Purphoros's bursts of destructive energy stand in sharp opposition to Thassa's gradual alterations. Purphoros regularly makes gifts for Thassa, most recently gifting her a new spear to replace her lost weapon.
Thassa has little use for the gods who oversee work she believes best left to mortals: Ephara with her cities, Karametra with her fields, Pharika with her tinctures, Mogis and Iroas with their armies. To Thassa's mind, her peers are building castles in the sand, unaware or unmindful that the tide will sweep them away.