Erika is in charge of Dr. Gheist's personal guard. Her mission involves not only ensuring that nothing untoward happens to the Doctor, but also detecting traitors that have infiltrated the G.H.E.I.S.T. and making them disappear, which is by far the part of the job she likes best.
GHEIST is an ultra-secret criminal organization that was founded at the end of the 70s by super-rich Doctor Sigmund Gheist. In order to increase its numbers, it has decided to take control of Clint City and its gangs by hook or by crook.