Marie hails from an area outside of the Canopy Kingdom known as No-Man's Land, a wasteland that used to be a country but fell during the war with the Canopy Kingdom. Along with her friend Patricia (who would later become the Anti-Skullgirl weapon Peacock), Marie was orphaned during the war and forced into slavery by a group funded by the Medici Mafia.

Seven years after the war, Marie obtained the Skull Heart through unknown means. She used it to punish the slavers who had tormented her and Patricia, but transformed into the Skullgirl in the process. However, her strong will allowed her to resist the influence of the Skull Heart and continue her quest of vengeance - having disposed of the ones who enslaved her and Patricia, she turned her attention towards their sponsors: the Medici Mafia.

After arriving in New Meridian, Marie set up base in the catacombs of the local cathedral. She joined forces with the mysterious Double, although the exact nature of their meeting is still unknown. Marie also came into conflict with "Last Hope", an elite squad of Anti-Skullgirl Lab operatives, and wiped them out. The sole survivor, Valentine, was coerced into joining the Skullgirl as her second elite minion.

Some time later, Marie discovered that a number of people around the Canopy Kingdom were seeking her out, each for their own reasons. She waited in the catacombs beneath the cathedral for anyone bold enough to challenge her, but the true version of events remains unknown.

Marie is quite difficult to fight even on Easy difficulty, due to her wide variety of "Cheap Shots" that can do a hefty amount of damage. She also tends to spam these moves without any respect for the Tension Bar of hers that never decreases. Her spammings does not count as infinite combos and as such, the combo escape cannot be used on her.

Marie cannot be grappled, though the scratch damage from the initial grappling is still dealt. Blockbusters that involves grappling (i.e. Cerebella's Ultimate Showstopper and Squigly's Daisy Pusher) are obivously ineffective during this battle

1st Form (Full Health):

Things will begin pretty calmly, with Marie floating in the air while surrounded by Skulls. This form will be the the easiest as she only uses and switches between 2-4 attacks:

Her first attack involves spewing out an endless array of skulls that constantly fly in towards the player to intercept an attack/force blocking. They do relatively minimal damage but can pose quite an annoyance to new players due to their erratic flight pattern and sheer number.
Her second attack being the most dangerous during this section. Marie will send clusters of Skulls towards the player at either a diagonal or horizontal angle depending on their current position. While dealing less than noticeable damage if blocked, they have a rather large hitbox that can cause trouble for new players due to the timing issue. If the skull trains connect they will tear off a huge chunk of health.
The third attack involves her summoning a pile of skeletons from undeneath the player's position to grapple their feet, causing slight scatch damage, then toss them across the stage for a moderate amount of damage. The player will become vulnerable to all subsequent attacks should this grapple connects. This is a move that she will spam very much during all of her forms so keep that in mind, though staying near her seems to lessen the frequency of her spamming this attack.
Marie's fourth attack creates a skeleton between her and the player. The skeleton will disappear after a while, but will explode violently should anyone touches it. Marie will use this trick to keep her distance from the player, where she can bombard them with even more skulls.
Rarely will she ever use a fifth move where she whacks the player character with her bone vacuum cleaner-scythe.

2nd Form transition (>2/3 Health):
Be careful as when she starts to transform she will emit a blue explosion which will seriously hurt the player should they be caught in it.

The attack, however, has a clear warning to when it will happen: Marie will cease all of her attacks for a split second and blue smoke will start billowing from underneath her. The explosion will take about half a second to actually deal damage so a wary player can dodge it if timed correctly.

Here's where things will begin to get a bit...tedious. Marie's form will have changed to one where she's floating in the air with a figure created by the Skull Heart floating right behind her. Marie stops launching skull during this phase. Yet, She has a new set of attacks for this form on top of her already existing attacks:

2nd Form (2/3 Health):

Her sixth move is one of her most annoying ones, where the figure behind her sends a shadow out to attack the player from multiple directions:
If the Shadow flies UPWARD, it will come down from ABOVE and counts as a High Attack, so block this one while Standing up for chip damage.
If the Shadow sinks DOWN into the ground it will be coming up from UNDERNEATH, block this by crouching.
If the Shadow appears and then just randomly disappears then it will rush out from either the FRONT or from BEHIND, simply block to avoid this. It does not matter if its blocked while standing or crouching, though standing blocks will result in less health loss.
There will be moments when Marie will get close to the player, allowing her shadow to jab at them and sends them flying across the stage for a moderate amount of damage.
​Marie's seventh move simply replaces her Mass of Skulls (2nd attack) for a random knight that will come charging at the player diagonally or horizontally. Blocking is slightly difficult here as the knight is sent out at random intervals, but if he comes straight towards the player he can be blocked with a stand guard; if he comes down diagonally her can be blocked with either a standing or crouching guard. Crouch-gurading a diagonal knight results in less damage.
The eighth move is one where she brings in a skeleton of, what seems to be, a dead Medici gang member to shoot at the player, pushing them back and damages them if not blocked.
NOTE:

It is recommended to end this phase using normal moves with an occasional Blockbuster. Do NOT waste Tension Bars here as the next part is much easier/harder with/without the use of Advanced Blockbusters.


Final Form transition (>1/3 Health):

Marie will explode in a blue explosion that can suck the player in and deals high damage. Like the 2nd form transition, she will cease all attacks before making this phase change, so stop hitting once she pauses and back away. If her health is drained before she can complete her transformation, she will die as soon as it finishes.

Final Form (1/3 Health):

This will be the most difficult (easiest if well managed) and grueling form of Marie. Marie is now merely bones; becoming nothing more than an organism surrounding the Skull Heart. The energy of the Skull Heart is now the only thing keeping her together, which is what must be attacked to hurt her.

She will use all of her attacks during this phase, but she will also become much more succeptible to damage. This is where an Advance Blockbuster comes in. Filia's Gregor Samson or Valentine's Savage Bypass can rip off her last chunk of HP in less than one minute.

Blocking does not make a difference at this point due to her attacks deals the same amount of damage, blocked or not.

GOOD LUCK :)