Drea is one of the Kelvan agents from the Andromeda Galaxy in By Any Other Name, a member of Rojan's small party that captures the Enterprise for the long journey home.
Drea is a Kelvan in the Original Series episode By Any Other Name. Like the rest of Rojan's party she was born on a generation ship from the Andromeda Galaxy and has taken human form to operate a captured Federation starship.
With Rojan, Kelinda, Hanar and Tomar she uses a paralysing belt device to take the Enterprise. Drea is put in charge of running the ship's key systems during the crossing of the galactic barrier and the voyage beyond, after most of the crew have been reduced to small dehydrated blocks.
Kirk, Spock, McCoy and Scott set out to overwhelm the Kelvans with the sensations of their new bodies, and Drea is one of the targets of this campaign of distraction. When Rojan finally agrees to turn back and seek a home in the Milky Way, she returns with the others.