Shadow Queen

"Then, you wretched fools... you will learn the error of your ways!"

- Shadow Queen

The Shadow Queen is the overarching antagonist and the final boss of Paper Mario: The Thousand-Year Door. One thousand years before the game's events, she arrived, hoping to conquer the land; she was defeated and sealed away in the Palace of Shadow, where she remained for the last millennium, with the game's main plot centering around the plot by the X-Nauts to revive her.

Background
According to legends, one thousand years ago, the Shadow Queen simply appeared one day, and waged war against the city where Rogueport now stands. She destroyed the city and all who opposed her, forcing the remaining inhabitants to surrender to the Queen's rule; she transformed a quarter of the city into the Palace of Shadows, and then made plans to conquer the rest of the world with her minions, including the three Shadow Sirens and her pet dragons, Hooktail, Gloomtail, and Bonetail.

The Shadow Queen then created the Crystal Stars, which hold the essence of the heavens, and planned to use them to re-mold the world in her desired image. The Queen hides the stars in fortresses and castles across the lands, and creates the Pit of 100 Trials and the monsters within it to all who oppose her.

While the Queen is near the peak of her power, four heroes—a Toad, a Goomba, a Koopa Troopa and a Boo—emerge to stop her by stealing the Crystal Stars and using their power against her. They gathered the stars, invaded her Palace, and attacked the Queen, destroying her body; her spirit survives, however, and is subsequently sealed in the foundations of the palace. Upon death, however, the queen curses the warriors, forcing them to take precautionary measures.

Paper Mario: The Thousand-Year Door
After a thousand years, Beldam enacts a plan to revive her through manipulation of the X-Nauts, who kidnap Princess Peach, setting off the events of the game. Mario and his friends collect all seven Crystal Stars, defeat most of the X-Nauts, and pursue Grodus to the Palace of Shadow in order to stop the plot once and for all. Unfortunately, Grodus is able to summon the Shadow Queen and presents Peach as a vessel for her to possess. Now reborn, the Shadow Queen prepares to enact her vengeance, and soon nearly destroys Grodus for thinking he could control her.

The Shadow Queen then notices Mario and his friends and offers them the position of her servants. If Mario agrees, the Shadow Queen will engulf the world with her foul magic, resulting in a Game Over for Mario, for Peach, and for the world. When Mario refuses, the Shadow Queen attacks him and his friends, intending to put them in their place, but finds that Princess Peach's body is impeding her power. The Shadow Queen assumes her real form, and for a time becomes impervious to Mario and his friends' attacks. After several further unsuccessful attempts to attack the Shadow Queen, the battle abruptly stops just as Mario and his friends are about to give up hope.

However, the Crystal Stars manage to travel to their home locations, allowing the people of each area to communicate with Mario. The goodwill and wishes of people the world over are enough to suppress the Shadow Queen's possession of Princess Peach; she regains control of her body long enough to give Mario all her remaining power. Restored, Mario and his partners resume their battle against the Shadow Queen; they are able to defeat and destroy her forever, and Peach regains control of her own body once again.

Super Paper Mario
In Super Paper Mario, the Shadow Queen cameos as a doll in one of Fort Francis' rooms that are filled with Paper Mario: The Thousand-Year Door character dolls and posters.

Super Mario-kun
The Shadow Queen also appears in the Super Mario-kun manga adaptation of Paper Mario: The Thousand-Year Door's plot. As with most characters in the manga, she displays more of a comic side.

Super Smash Bros. Ultimate
The Shadow Queen, in her possessed Princess Peach form, appears as a Spirit in Super Smash Bros. Ultimate. Her connection to the Shadow Sirens is given an indirect reference in her unlock requirements, which requires Vivian's spirit to be summoned alongside a Gengar spirit core.

Powers and abilities
The Shadow Queen is an immortal demon, having survived for a full thousand years while being sealed in the Palace of Shadow. She can also possess other people, and has a variety of magic at her disposal, which she uses to create powerful creatures and objects such as the three dragons and the Crystal Stars. However, her vessel may be able to suppress or co-opt her influence temporarily if they possess particularly strong willpower.; near the second half of the final battle, Princess Peach manages to regain control long enough to fully heal Mario and his party.

In battle, while in her true form she is immune to normal and defense-piercing attacks, and can only be made vulnerable with the power of the Crystal Stars. She is able to use her hands to drain the health of her enemies and pierce their defenses; they are also capable of smashing opponents to the ground, and are considered separate enemies that can be targeted individually. When the hands defeated, the Shadow Queen can revive them the following turn. The Shadow Queen is also able to strike her opponents with lightning that pierces her target's defenses. When low on health, the queen will often resort to attacks that induce poison, confusion, or allergies that prevent status changes.

One of the Shadow Queen's stronger attacks is the use of several shadowy hands that come up from the ground and drag Mario or one of his partners down into the shadows and damage them with several attacks or stampede them for heavy defense-piercing damage. The queen will also attack the audience members with these hands to drain their energy to restore herself to full health and power. Her strongest attack is a series of dark energy waves that hit Mario and his partner for heavy damage, but this attack takes a turn to charge up, allowing Mario to avoid it with Vivian's Veil ability. Additionally, the Shadow Queen also has the ability to temporarily raise her attack and defense by 3.

Personality
The Shadow Queen is a demon who cares only for herself and her aspirations, particularly conquering the world and remaking it in her image; she seems to rule her followers through fear rather than loyalty, as she often uses her powers to intimidate them. The Shadow Queen is motivated by power and pride above all else, and is not afraid to assert her authority over anyone she sees as weak or insubordinate; despite Sir Grodus playing a major role in her unsealing, she blasts his head off for daring to suggest that she obey him. She then takes on Mario and his party, believing them to be too weak to handle her.

Some of the Shadow Queen's speech and behavior vary somewhat between the Japanese and English versions of the game. In the Japanese version, she speaks in a considerably more down-to-earth manner. For example, when she sees Mario and his party members, she describes them as looking "agreeable", and claims she will "let bygones be bygones" when offering them a second chance to serve her. In the English version, she speaks more formally, and is more condescending, backhandedly describing Mario and his party members as looking weak but possibly useful.

Physical description
While possessing Peach, the princess's skin turns paler with dark makeup, and her dress becomes dull purple with white detailing. She wears a similarly-colored cloak with a high collar; the collar causes her hair to appear significantly shorter as well. Peach's crown and jewelry turn red and take a similar shape to those of the Shadow Queen; her face also takes on a more cruel expression.

In her true form, the Shadow Queen appears as a shadowy purple demon, with a "starry" body that takes on an elongated form during cutscenes and a spiral-shape during the final battle. Her hair underneath her massive crown is a grayed purple, and her "face" only has small pale lips visible, similar to the Shadow Sirens; in Super Mario-kun, she possesses a large mouth with jagged teeth as well as big, scowling blank eyes. The Shadow Queen has large hands that only appear connected during cutscenes, and are shown as disembodied during the battle.

Trivia

 * Her text box graphic is the same as Bonetail's, as well as Mimi's true form in Super Paper Mario.
 * Despite being the final boss and the game being able to be resumed from after she is defeated, the Shadow Queen only offers one star point upon defeat. This is also true for Bonetail.
 * If the player Superguards her hand's HP-draining attack and prevents the damage, the sound effect for HP recovery still plays.
 * In the Japanese version of the game, it is not possible to Superguard any of her attacks.