Thassa's History
Thassa is the god of the sea and is also associated with aquatic creatures and the secrets of the briny deep. She is also the god of ancient knowledge, murmurs, gradual change, introspection, vast distances, long voyages, and far-ranging searches. Thassa can also be described as the god of patterns, such as tides, currents, ripples in water, and even the passage of time.
Thassa is the god who is least likely to be satisfied with the status quo, but in the meantime, she is also the least likely to rush to change. She works slow, eventual, and unfolding change to everything by resculpting the land, changing coastlines, and upending institutions. When she speaks, she usually does so in the future tense, always referring to what tomorrow will bring and uninterested in the reality of today. Thassa is slow to anger but implacable once roused. Her anger grows like a rumbling, cresting, unstoppable wave, destroying whole villages with its fury — then subside with the tide, dragging the evidence of her wrath out to sea.
Tritons and the humans of Meletis comprise most of Thassa's worshippers, as well as all who venture out to sea, whether for exploration, commerce, or war. Despite the tritons exalting her above all other gods, she shows no favoritism toward them, being equally impassive to all mortals. Thassa is worshipped with offerings of fish and salt by the poor, offerings of pearls and nacre by the rich, and with murmured prayers and quiet contemplation by all. When Thassa wishes to see a mortal, she does not issue a summons or grant a vision requesting a visit: the sea simply brings her guest before her.
During the events of Xenagos's ascension, Thassa came into conflict with the merfolk planeswalker Kiora, who was claiming to be an avatar of the deity known as Callaphe. It was this lie that brought Kiora into the path of Ajani Goldmane and Elspeth Tirel. The pair sought out Callephe for her skills, trusting her ability to bring them to the Temple of Mystery, the ancient tree at the edge of the world.
Kiora agreed to do so, but for purposes she wasn't forthcoming about, dismissing it with a wall of good cheer. She led them along for the ride as she pursued her own agenda, never letting it slip that she was not who she said she was. The truth finally came out shortly after they set off, as Kiora brought them to the sunken city of Arixmethes. It was no city at all, in truth, but a massive kraken upon whom a city had been built. Thassa would not allow Kiora to take the beast from her but first assisted Elspeth and Ajani in their journey.
The pair taken care of, Thassa turned her attention to Kiora. After a fight involving many sea monsters and kraken (some of them summoned from other planes), Kiora barely escaped with her life, but managed to steal Thassa's magical bident Dekella. Kiora has yet to return to the plane for fear of retribution from the enraged God.
When Heliod declared war on the rest of the gods of Theros, Thassa fought back and raised up the real Callephe from the underworld as her demigod champion in the conflict.