Paper Mario: The Thousand-Year DoorEdit
Some time before the events of the game, Grodus and his X-Nauts met up with Beldam, who told him about the legendary treasure behind the Thousand-Year Door, that it was an evil demon called the Shadow Queen, who would need a body of a pure maiden to possess, and that she was bound to obey whoever awoke her. This last part was a lie; Beldam said this only so Grodus would want to bring her back and use her to take over the world. Grodus began searching for the Crystal Stars required to open the Thousand-Year Door.
Beldam, posing as a merchant, searched for one the Shadow Queen could possess, and who could open the chest containing the Magical Map, which would show them to the Crystal Stars. She soon found Princess Peach, who was able to open it, but a strange old man (presumably Toadsworth) showed up at the last second, preventing Beldam from kidnapping her. By the time she did kidnap Peach for Grodus, Peach had already sent the map to Mario. Grodus soon heard that Mario had taken the Crystal Star they were hunting in Hooktail Castle, and after learning Mario's identity, he sent his general, Lord Crump, to the Boggly Woods, along with Beldam and her sisters Marilyn and Vivian. Mario defeated them all and took the Crystal Star.
Grodus also never told his minions about his plan to have the Shadow Queen possess Peach; when Peach, disguised as an X-Naut, asked him, he refused to tell her. However, she did learn from him that his goal was to conquer the world.
Grodus began to take some measures after Mario got the fifth Crystal Star, and sent Beldam to spy on Mario in the shadows. Beldam learned the sixth Crystal Star's location, but stole a fake Crystal Star instead by mistake. Grodus was angry about this, and became even more enraged when one of his X-Nauts told him that his main computer, TEC, had betrayed him and was helping Peach. Grodus entered TEC's room with two X-Nauts and shut him down (he survived by backup power, but later blew himself up to destroy the X-Naut Fortress). He then took Peach to the Palace of Shadow.
Mario and his partners finally found the elusive Grodus in the Palace of Shadow, and he revealed that his true intentions were to let Mario collect the Crystal Stars, and it wouldn't matter whether Crump, whom Grodus entrusted the last Crystal Star to and views as his "least competent underling", beat him or lost to him. Mario fought Grodus and defeated him, however, having seen this possibility, he revealed Peach, trapped in a green orb, and threatned to kill her if Mario attacked. He tormented Mario with lightning bolts, but as he was about to kill Mario (or Peach, if the player chooses NOT to attack him), Bowser suddenly fell through the ceiling and landed on Grodus.
However, Mario was distracted fighting Bowser. By the time Bowser was down and out, Grodus had escaped into the Shadow Queen's tomb with Peach. He awakened the Shadow Queen, who possessed Peach. Grodus commanded her to destroy Mario and his partners, but the Shadow Queen, contrary to what Beldam had led him to believe, would not take orders from anyone, and destroyed his body, leaving only his head, which she apparently trapped in another dimension, saying her powers were not yet fully restored (explaining why she didn't kill him).
Grodus reappeared after the Shadow Queen was defeated, and began living peacefully with Lord Crump and the four remaining X-Nauts in Poshley Heights. Grodus never caused any trouble again, and was also still only a head.
Grodus has 50 HP, 7 ATK, and 1 DEF. He has lightning and fire attacks that hit Mario and his partner. He can also make himself dodgy. He spawns two Grodus X's per turn, which raise his defense. If he has four, he is invincible, and starts the battle this way. It is easiest to use Vivian's Fiery Jinx on him every turn to eliminate the Grodus X's. It is also advisable to enter the fight with about 80 Star Points, as there are no chances to heal between this battle and the next one, against Bowser.
Super Paper MarioEdit
It is mentioned that Grodus got his own TV show, the Grodus Chronicles, which was written by a writer named Garamond from Flopside. Francis watches this show and often talks about it. The X-Nauts also appeared in a TV show, Starship X-Naut, which also has its video games and comic series.
- The responses for whether or not to attack Grodus after defeating him are in reverse. If you choose to attack him, he tries to kill Mario. If you choose not to attack him, he tries to kill Peach. It should be the other way around.
- The audience for Grodus's battle consists entirely of X-Nauts.
- His plan of letting Mario collect the seven Crystal Stars and bring them to him, along with his use of the line "Whether he beat you or lost to you, either way the Crystal Stars would be together and mine" is, perhaps by coincidence, similar to Sthertoth, the antagonist of Bomberman 64: The Second Attack, who sent the Astral Knights to defeat Bomberman and take his Elemental Stones, but in the end was only using him to collect the stones, and says "In the end it didn't matter. Either way, I still got the stones."