Nassana can be found in the Embassy Lounge of the Presidium. She will not interact with Shepard while on the Citadel, but will later transmit a message to the Normandy requesting his assistance. She explains to Shephard that her sister, Dahlia Dantius, has been kidnapped by a rogue mercenary group and taken to the planet Sharjila in the Artemis Tau cluster. Nassana claims to have already paid the ransom, and that the mercs had not followed through on the deal. It is later discovered that Dahlia was in fact their leader and that Nassana was blackmailing her. If Shepard finds Dahlia independently without talking to Nassana, she becomes disappointed that she did not have the chance to manipulate the Commander.
Mass Effect 2
In the second game, Shepard runs into Nassana in the Dantius towers on the planet Illium. Due to her blood-thirsty business decisions, Nassana has fallen prey to party member Thane. If the player dealt with her in the previous game, dialogue may differ slightly during their encounter. If they player has met Nassana previously, she believes that Shepard is the assassin and claims that is it ironic that the Commander killed her sister and is now going to kill her. She is eventually shot and killed at point blank range by Thane regardless of the players dialogue choices.