Desdemona

Desdemona is a human child, about 9 years old, who has psychic powers (read: 6 levels in the Mystic class). She escaped from an illithid testing facility. The party found her in the wilds of the underdark eating a raw umber hulk corpse, and adopted her to their cause. She apparently is very familiar with Mysa'aor and Fiend's Mirrors, and is leading the party to the location of the mirror they promised Mysa'aor they would open.
Despite her age and fragility, Desdemona is extremely fast, usually very quiet, and is incredibly smart. Her interactions with the party have mainly consisted of vague, short instructions, slightly irritated glances, and the occasional brief snark, but usually she is eerily silent and kind of unsettling. At one point in the underdark, during the party's excursion into the Ghost Wasp lair, she grew angry with Barkley, who was pestering her. The mystic used her powers to convince Barkley that Godfrey was on fire, causing panic amongst the group and upsetting Barkley badly. Godfrey yelled at Desdemona, telling her that she shouldn't do to other what the illithid did to her, and in her anger, she tried to do a psionic attack of some sort on him, which failed. She stormed off after yelling at Godfrey. Olivia managed to defuse the situation and convinced Desdemona to come to the surface world with the party after opening the Obscura Fiend's mirror.