Marie Kanker is the middle sibling of the Kanker Sisters (older than May but younger than Lee). She has short blue hair that covers her right eye; it is not known whether her hair is dyed this color or comes this way naturally (as is assumed with Rolf). She is in love with Edd, and many times he has been victim of the extreme love she has for him. She is knowledgeable about automobiles, and it is speculated that she is able to fix vehicles on her own. She most commonly wears a black tank-top that halts right above her bare midriff, a pink belt, and green non-camouflaged BDU pants. Her overall appearance allows one to believe she is a fan of rock music. She is often shown as crafty and sneaky, especially when compared with her sisters. Her nails are painted an ominous amber. She wears a sleeveless green shirt and polka-dotted boxer shorts to bed. Marie appears to have a slight rural Midwestern accent.

Marie is an easily angered, intimidating, and rather tomboyish girl. She has a very menacing personality, perhaps best exemplified in Key to My Ed when the presence of her and her sisters manages to stop a rumble and scare everyone away from the Lane. She is also shown to be quite strong, as in Tag Yer Ed she is able to defeat all three Eds in a wrestling match in less than 20 seconds. She has also been known to easily rip out Lee's armpit hair, rip the covering off of a speaker, and restrain Eddy with nothing more than a pair of underwear.