One of Data's twin synthetic daughters, whose murder set Jean-Luc Picard on his search for her sister Soji.
Dahj was a synthetic woman created from a single positronic neuron of Data, with an organic-seeming body and no knowledge of her true nature. When Romulan assassins attacked her and killed her partner, hidden combat abilities activated and she defeated them, then sought out Jean-Luc Picard after experiencing visions of him.
Picard found that a painting Data had given him, titled Daughter, showed a figure resembling her, but before he could protect her she was killed in a second attack by the Zhat Vash. Her death drove Picard to find and save her twin, Soji Asha. Dahj was played by Isa Briones.