Rakal (Major)

From Memory Alpha, the free Star Trek reference.

Major Rakal was an operative in the Romulan Tal Shiar.

In 2369, she was killed by members of the Romulan underground movement so that Deanna Troi could be surgically altered to take her place. As Rakal, Troi could then take part in a covert mission to enable the defection of Vice-Proconsul M'ret and his aides to the Federation. (TNG: "Face of the Enemy")

As Rakal, Troi wore a unique "harness" with one additional strap over her Romulan uniform. It was never used again.