King Boo
Used by
Jay's Wing
Boolossus, Boo Matter, other Boos, Bowser, The Koopalings
Mario, Luigi
1-94 meters
Nintendo Character

King Boo is a character used by X Jay's Wing X.


King Boo is shown to have a deep hatred for the Mario Bros., especially Luigi after he defeats him in Luigi's Mansion. He says that he fears nothing except the Poltergust 3000, although in Super Mario 64 DS he admits that Wario's face scares him. Also, in Mario Super Sluggers, King Boo says that he finds little Boos cute and says that he actually considers his Boo minions his friends and cares for them. This is shown in Luigi's Mansion where he goes after Boolossus after he is captured by Professor E. Gadd. In Mario & Sonic at the Olympic Winter Games, he says that he is unbeatable at the Alpine Skiing events, though this is proven false when the player beats him. He doesn't seem to care for ghosts that aren't Boos, however he will use them in his plans as tools rather than subjects. After breaking out of the portrait he was placed in at the end of Luigi's Mansion he displays a complete disregard for anything that interferes with his revenge and displays several sociopathic traits including a disregard for others well being and at one point nearly causes the Mario Universe to collapse. King Boo also loves to scare and toy with his opponents. Despite King Boo's huge size he will still cover his face in fear when looked at much like a normal Boo showing that he still has a shy nature like his minions, however also like a normal Boo he will attack when his foes back is turned. Professor E Gadd also comments on how King Boo redecorated the Treacherous Mansion to make it scarier. He also goes into fits of rage when his plans don't go the way he wants. Although King Boo is much larger than regular Boos, he is not the largest of the Boos. However, even gigantic Boos like Boolossus follow his leadership despite their superior size. Lastly, King Boo has a distinct cackle, which is significantly lower in pitch than other Boos.

Likes and dislikes


  • Horror Stuff

    King Boo as he appears in Super Mario Sluggers.

  • Playing games
  • Mario Party
  • Scaring characters
  • Jewels


  • Vacuums
  • Losing
  • The Mario Bros.


Before the events of the RPVerse, King Boo lived in a mansion with other boos. When Mario attacked boos and invaded his boos' houses for seemingly no reason, King Boo decided to get revenge. He then gave Luigi a fake letter to a mansion. When Mario arrived, he captured him inside a painting, after recruiting ghosts to do his bidding. Later, though, Luigi came and foiled his plans, trapping him in a painting himself. After that, he escaped, and haunted a casino in Hotel Delfino until Mario defeated him. He then captured Mario again, but was defeated once more by Luigi.

King Boo first appeared in the RPVerse when Mario and Kirby went into the Ghost House. He got mad when they started beating up Boos. When they went on an adventure, he decided to go with for an unknown reason. They encountered Shadow Mario before going to White Wafers.  They then were attacked by Bowser's ship and the Koopalings.  

King Boo at some point started teaching FeMuto about the powers of necromancy. The Ghost King was then asked to help with a problem with Ao Oni by Hydrogeon and Applejack. He told them to lure them somewhere else, so they did.

Later, a possibly different King Boo attacked the city of Udaipur when the hotel he was haunting was destroyed. He fought against Giant Slalom and Kashima C but was destroyed when he ate peppers, burning him from the inside out.


  • Intangibility
  • Floating
  • Shadow Ball
  • Can turn invisible
  • Can materialize things
  • Is able to regenerate from his crown
  • Can spit blue fire
  • Teleportation
  • Gains more power in the presence of other Boos
  • Size-shifting
  • Can create portals to a Ghost Dimension
  • Can electrify terrain
  • Creates illusions
  • Can fire a laser from his crown
  • Summoning Boos
  • Experienced kart racer
  • Experienced Golf player
  • Experienced Tennis plyer
  • Exerienced Baseball player
  • Can survive Mario Party games
  • Can revive others as Boos
  • Is a ghost, so... he kinda can't die, since, ya know, he's already dead?
  • Doesn't need to eat, sleep, ect.


  • The Poltergust


King Boo's Illusion - Luigi's Mansion Dark Moon-0

King Boo's Illusion - Luigi's Mansion Dark Moon-0