She's an Eraser. A professional social media assassin for hire. Hire her to mount a clandestine campaign of social media annihilation against your target. Pay her, then watch the damage seep in.
She undermines your target's social media profiles in numerous subtle but eventually toxic ways. She first studies the target's profiles to understand his or her interests, opinions, etc. and then mounts a campaign of discredation. Multiple fake profiles that seem genuine, each rebutting the target's posts with cleverer, more accurate contrarian replies. Subtle hacks to the target's account that he or she might not notice (photoshopping photos to make them embarrassing; changing the text on old posts, likely forgotten by the target, so that they are somewhat offensive or questionable; adding "likes" and affiliations to inappropriate things).
After a few months, the target's social profiles slowly become increasingly toxic, in ways that the target will possibly overlook (unless they play very close attention to their profiles) until the damage has been done.
When the target wises up and closes an account, the Eraser has created a virus to automatically enact the same process to any future social media accounts the target creates. Basically, the target's social media profile is permanently tainted until you call the Eraser off. Great stuff for blackmail or settling old scores.