Shego

Much more competent than her boss Dr. Drakken, the Friends saw potential in her from early on when she was a member of Team Go, sensing her boredom with the group. Approaching her, they offered her a power boost and convinced her to betray her family. She's been responsible for most of Dr. Drakken's few brushes with success. However, she's paid off her debt and the Friends are fairly unsatisfied with her, due to her displaying more and more Friendly Enemy tendencies with Kim (if not outright Foe Yay).