A synthetic young woman created from Data's positronic neurons, unaware of her own nature, who seeks out Jean-Luc Picard in 2399 and is killed by Zhat Vash assassins.
Dahj Asha is played by Isa Briones in Remembrance, the first episode of Star Trek: Picard. She lives in Boston and has just been accepted by the Daystrom Institute when masked intruders kill her boyfriend, and dormant combat abilities allow her to destroy them.
Guided by a vision of Picard's face, she finds him at his vineyard in France. He connects her with a painting by Data called Daughter and realises that she is in some sense the android's offspring. She flees, then meets him again at the Starfleet Archive in San Francisco.
Romulan agents attack on the rooftop there, and Dahj dies when a damaged weapon explodes. Picard learns from Agnes Jurati that such synths are made in pairs, which sets him searching for her twin, Soji, and for Bruce Maddox.