Palace of Shadow

The Palace of Shadow (Japanese 闇の宮殿/やみのきゅうでん Yami no Kyūden) is the final area that Mario and his comrades visit in Paper Mario: The Thousand-Year Door, and is where the Shadow Queen resides. It is found accessed by going through The Thousand-Year Door. The Palace is one quarter of the old city that was ruined 1000 years ago. Over the years during which the Queen reigned, the Palace became rich with stolen treasure.

In this palace, the Shadow Queen possesses Peach, who Sir Grodus had delivered to her. Mario and company drudged through the palace and its inhabitants, including the middle sibling in the "tail" family, Gloomtail. Mario and his allies later fought with the Shadow Sirens, who now consisted of Beldam, Marilyn and Doopliss. Soon after, Mario's party finally made it to the Shadow Queen's inner sanctum, where Sir Grodus was. Mario and his party defeated him, and also defeated King Bowser and Kammy Koopa, who literally "dropped in" on them unexpectedly. Sir Grodus retreats to the final room to use Princess Peach as an offering to the Shadow Queen.

The first room is rich and very detailed with roses and patterns. Past this is a bridge across an expanse of water, the cave "ceiling" can be seen here. The room afterwards is a large staircase that goes even farther underground. Later, a garden area shows off some streams and the Riddle Tower. After the tower's riddles are all completed, some ancient machinery will activate, causing the long hallway leading to Gloomtail to collapse, revealing a lower area filled with enemies. One of the last rooms is a huge chamber with odd pillars, and then, the throne room where Grodus uses Princess Peach. A secret door leads to a huge staircase down to the crypt containing the Shadow Queen.

Enemies

 * Bombshell Bill
 * Bombshell Bill Blaster
 * Bowser (Mini-Boss; fought after defeating Grodus)
 * Chain Chomp
 * Dark Bones (Mini-Boss/lesser enemy)
 * Dark Wizzerd
 * Dry Bones
 * Dull Bones
 * Gloomtail (Mini-Boss)
 * Sir Grodus (Chapter 8 Boss)
 * Grodus X (backs up Grodus in battle)
 * Kammy Koopa (backs up Bowser in battle)
 * Phantom Ember
 * Red Bones
 * Shadow Queen (Final Boss)
 * Shadow Sirens (Mini Boss)(with Doopliss)
 * Swoopula

Trivia

 * According to the Magical Map, the Palace may be somewhere near the middle of the ocean.
 * The music for the second half of the palace is a darker remix of the classic Super Mario Bros. Castle theme.
 * The true hidden treasure, found by Professor Frankly, was actually a Dried Shroom. Frankly believes that this is a fantastic discovery because it is proof that civilizations ate mushrooms 1000 years ago. It's possible that this mushroom was an Ultra Shroom or more miraculous back 1000 years ago, but dried out over time.
 * In nearly every one of Goombella's descriptions of the rooms of the palace, she mentions an aura that makes her feel extremely uneasy, most likely the extreme evil occupying the thousand-year old palace.
 * Oddly, Mario had to go through many trials to get to the Palace of Shadow, while Bowser just fell through the ceiling.