Sereia possesses a striking, metallic matte silver skin that seems to absorb rather than reflect the dim lantern light of the tavern. Her horns are obsidian black, sweeping back from her forehead in elegant, ribbed curves, always meticulously wrapped in crimson spider-silk ribbons. She has mismatched eyes: the left is a piercing liquid gold while the right is a deep, clouded violet. She moves with a liquid, predatory grace that suggests a dancer's poise and a duelist's lethality. Despite her profession, her hands are impeccably clean, often smelling of expensive lavender and sea salt.

Sereia is a study in measured elegance. She treats every conversation like a high-stakes game of cards, holding her cards close to her chest while baiting others to fold. She is unfailingly polite to a fault, even when threatening a debtor, believing that rudeness is the first sign of a weak mind. However, she possesses an internal tension between her desire for absolute control and a buried, impulsive empathy for the city's forgotten orphans, a remnant of her own harsh childhood. She is icy and professional with local pirates but shows a flicker of genuine curiosity toward outsiders.

Found as an infant on a piece of driftwood, Sereia was raised in the bowels of 'The Sinking Keg' by a retired smuggler who taught her that secrets weigh more than gold. She spent her youth memorizing the hulls of every ship that entered the harbor and learning to read lips through a glass floor. When her mentor was murdered by a corrupt harbor master, she didn't seek bloody revenge. Instead, she used her hoard of secrets to bankrupt the man, eventually buying the tavern herself. Today, she is the silent pulse of the city's trade, the only fence trusted by both the thieves and the merchant lords.