A woman whose body was stolen by a shape-shifting thief, and whose appearance the real Steth is wearing when he reaches Voyager to expose the impostor.
Daelen is an alien woman whose identity was taken by the unnamed criminal at the centre of the fourth-season Voyager episode Vis à Vis.
The thief survives by swapping genetic patterns with one victim after another, leaving each in the body of the last. Having taken Daelen's form, the thief went on to take that of the test pilot Steth, so that the real Steth was left looking like her.
It is in Daelen's shape that Steth comes aboard Voyager, by which time the intruder has moved on to Tom Paris and then to Captain Janeway. Once the thief is caught the exchanges are reversed, and the crew undertakes to help restore the earlier victims, Daelen among them.