Personality Karen is shown to be laid-back, shown with her calm general expression, but is overall pessimistic. She also takes her jobs very seriously, to the point that she has to seriously deal with others who annoy her working such as Mario, and is not above using violence as a method of control. Despite this, she seems to be enamored by cuteness, as she took a liking towards JubJub Boopkins in SMG4: Mario Does His Laundry.

However, she is shown to not like working; in SMG4: Mario Gets His PINGAS Stuck In Car Door, she was relieved when the store she was working at was robbed and blown up by the Mushroom Robber. In fact, Karen comes off as being rather cynical and a little nihilistic, such as keeping a straight face in many situations that turn out deadly, though she can act with surprise if the action spikes up.

She is shown to be extremely protective of her children and her loved ones and cares for them very much despite her negative outlook on life, though she does not tend to tolerate her son Zack's antics. While she is by no means perfect, she does prioritize them over everything else, even resorting to extreme bouts of violence if necessary even to friends such as Luigi and Mario.

History Karen makes her debut in SMG4: The Mario Documentary, working as a barista at a local Starbucks. She gets annoyed by Mario sneaking around her and scared him away with her shotgun. She is then seen again trying to get Mario off the store for trying to camp outside of Sundays but was kicked in the face. She would later send him and his tent to a garbage dump.

She makes a cameo in SMG4: Mario Goes To The Zoo, where she was at the zoo being burned at the stake by the pig army.

She makes her first major role in SMG4: Mario Does His Laundry, working as a laundry aide in a laundromat.

Her three kids make their debuts in SMG4: How To Train Your Mario.

In We Must Kill Mario, it would be revealed that she used to be an assassin before she quit her job in order to raise her kids but picked it up again temporarily since a criminal had appeared could be a threat to the world and her children.

Over time, Karen lost numerous jobs and was no longer able to pay the bills. In SMG4: Hobo Mario she lost her house and searches for a residence to stay with Mario’s help, but she can't take it anymore and tells the truth of her home status, but thanks to Mr. Monopoly, Karen got her home back. In the Same Episode, it's revealed that Karen had a difficult past. She was abandoned by her parents and grew up on the streets. She was subsequently hired by Hitman Inc, which is how Karen earned her money. "You screwed with the wrong family."