Ro Laren

Ro Laren was a renegade Ensign on board the USS Enterprise. She was posted to the ship after being suspended for negligence, which led to the deaths of eight officers. She had a shaky start to her new career, striking up an immidiet rivalry with Riker. She eventually had to leave the Enterprise due to her bad attitude, and was retrained at the academy from scratch.

After being retrained and given the rank of Lieutenant, Ro was reassigned to the Enterprise to be sent onto a secret mission into a terrorist cell that tried to destablise the relationship between the Federation and the Cardassians. After initial success, Ro eventually defected to the terrorists as she felt she belonged there, and Jean-Luc Picard refused to allow his crew to kill her.