Thessaly's father and mother were both Pathfinders... and in some ways, that's all they had in common. Thessaly's father was an Ulfen man of some renown, a member of the Ulfen Guard of Taldor, Erik Leifsson, called Erik Axe-heart. Thessaly's mother is an elf named Arindala, a student of the arcane arts. Erik was an impulsive man, honorable but often reckless, a terrible foe on the battleground but a simple man in times of peace, with simple pleasures... and Arindala was sophisticated, a scholar, a player of subtle and long-term games. Still, in the course of many missions served together, the rough Ulfen and the inquisitive elf struck up a romance, which became a marriage.
Yet, the pressures that push people together in times of adventure and danger can mean that those relationships dissolve like paper in water, when the adventure has passed. As the couple grew older, they began to grow apart-- Arindala wished to settle in Kyonin, turn to a more studious lifestyle, and leave behind what she called the amusing indiscretions of youthful curiosity and wanderlust. Erik, on the other hand, wished to stand in battle and seek out evil to fight for as long as his body would bear him.
If the two had not had the problem of a daughter, between them, then they might have parted their ways more amicably, and without further incident.
But, there was a daughter. Her mother had named her Thessaliel; her father called her Thess. From the time she could walk, he had pushed toy swords into her hand; from the time she could speak, her mother had pushed her towards books.
For the sake of their daughter, Erik and Arindala struck an uneasy bargain; half the year they would spend in Kyonin, or in other major cities that boasted reputable libraries and colleges; the other half they would travel to more active climes, accepting field missions, or visiting Erik's family in the Lands of the Linnorm Kings. For two years they attempted this, before both decided it was untenable; the new bargain was to be that for half the year, Thess would spend it with her mother, in Kyonin; and half with her father, whereever he might be. Each half-year they met at the Grand Lodge in Absalom to pass her off.
Thus, Thess grew up torn between two very different worlds. She loves the physical life her father leads-- steel against steel, mountains to climb, strange beasts to be seen and fought. But she sometimes cannot help but feel superior to his lack of education and his inability to see the big picture, to think long-term. With her mother, Thess has always enjoyed books and learning, the power of knowledge, and she dreams of being able to command a spark of lightning or fire for herself. But her mother always says it takes near a decade to learn the first spells of wizardry, and Thess's half-elven heart cannot stand the thought of a full ten years spent in nothing but study. She is also stung and piqued by the condescension and superiority the elves often display towards her as a half-breed.
On the whole, Thess prefers her father's world, and has learned more of the martial path than the wizardly one. However, her father is aging: Thess herself is but just past the mark of maturity for half-elves, and already she can see grey in his hair, and begins to see him losing his combat edge. She knows she will outlive him-- possibly by seventy or eighty years-- and the knowledge is cold as northern snows.
This inner turmoil and sense of being torn in two directions has made Thess into a cynical and sarcastic young woman. Outwardly, she affects crude mannerisms, taking after the Ulfen in most social contexts-- ready to drink as hard as any man, arm-wrestle at any invitation, and pretending disdain for both high society and for arcane magic.
She joined the Pathfinder Society as it was one of the few things her parents could agree on. Now, Thessaly tries to find her own path, and figure out who she is.