Sia is a vendor who collects and sells items while travelling all across the world.
She likes collecting rare items, from both land and sea. Ever since she was young, she liked searching the sea for hard-to-find pearls or unusually-shaped corals. From there, her interests spread to terrestrial items, and she realized that she needed resources to obtain the items she wanted. Sia started her business with items from her collection, and the rare items only found in the deepest parts of the sea sold out quickly. She felt fulfilled seeing people in delight after buying her items, and she decided business was her calling.
Because she wasn't interested in wealth or appearances, she wore modest clothes and spread her items out on nets and cloth. This led her to be easily picked on. Sia, who didn't like conflict, tried to avoid it by selling her items at a lower price and paying street tax despite experiencing losses. But as time passed, she experienced difficulty adapting to the rapidly changing trading posts of the city, and the amount of conflict that the the influx of people brought on started to get out of hand. In the end, Sia started to seek out remote places that allowed her to focus on her business. Soon, Sia became a kind of legend among tradespeople as someone who sells rare items but is difficult to meet.
Once a year, she stops by a beach town and does business there for a while. The town she visited after leaving the city was small and isolated, but the people there were so happy with the items Sia brought that they treated her to tea and snacks. Sia, who was moved by the kind treatment, visited the town every year. She became close to the townspeople, even helping them with town matters and having fun with them. To repay her for her efforts, the townspeople gifted Sia with a giant cart in the shape of a shop. Sia, who always struggled to move her items, is said to have burst into tears by the gift. Because of this, that town became more important to Sia than any other big city.
Sia goes through great changes thanks to the town. As more people started flooding in with the passing of time and the town's advancement, Sia also began to get involved in various incidents. Sia, who couldn't abandon the town like she did other places, realized that simply running away from disputes was not the answer. She began to dress herself up so she wouldn't be disrespected, employed the eloquence she mustered through years of business experience, and took advantage of her mermaid powers to confront conflicts that threatened the town's peace.