Setsuna Moon

Located West of Golden Sun territory, where the city proper gives way to rural slums. This shop is barely more than a shed, and one must lean over the gated doorway to peer inside. The space is littered with jars of revolting, pickled ingredients, and flasks of bubbling potions hang from the ceiling. The alchemist Setsuna, a diminutive young woman, is always seen cross-legged and brewing a potion. Her manner is curt and sinister - she is clearly not as she appears.
She seems to have the ability to read thoughts or secrets, as she outright pronounced one of Yunhu's darkest secrets in order to intimidate him.
She can brew any potion, but the real reason to buy from Setsuna is if you want a special (and usually illegal) substance or a powerful spell to be cast. In exchange she usually asks for something suspicious. For example to create a novel party drug to offer to the Blue Orchids, she requested a lock of hair from Lun and a fingernail clipping from Yunhu. The two were then plagued by nightmares the same evening. From this the group deduced that Setsuna is likely a hag, and casting Detect Evil & Good also revealed that she is a fiend.
In return, they got a strange silver powder (dubbed by the group as 'Glittering Satsuma') which when burned transported the group to the Feywild. Investigations in the Feywild implied that Setsuna used to be a fey lord (nicknamed 'Our Lady of Dusk') who traded her power for passage to the material plane. This was likely done to escape The Great Duty that brought the Feywild to ruin.
Despite her fall from grace, Setsuna is still powerful, cunning and very dangerous.

Setsuna