Marcy is, as per her appearance, a bratty little kid. Somehow or
another, she fights alongside Karsh and Zoah in a couple of your encounters with them. While nowhere near the other two in
terms of strength, she makes up for it with special attacks and magical ability. Oh, and her unique tech skills of course.
Recruitment
Marcy joins automatically (along with a host of others)
after rescuing Riddel from the Porre Army.