King Boo (Earth-1344)

"I am not afraid of you, fool! I fear only that infernal Poltergust 3000 you carry on your back! Stupid machine! But I am a KING among Boos! I swear it... I shall fear no mere house-cleaning device!!"

- King Boo

King Boo is the leader and king of the Boos, the ruler of the Paranormal Dimension, the archnemsis of Luigi and the main antagonist of the Luigi's Mansion series. He is sinister, clever, and determined. His powers include causing objects to appear out of and disappear into thin air, and control over fire, ice, and lightning attacks.

Personality
King Boo is shown to be ruthless, sadistic and cruel. He despises the Mario brothers, with his ultimate goal being to trap Mario, Luigi and their friends inside picture frames forever and take over the world.

King Boo is shown to be greatly annoyed by Hellen Gravely's failure to capture Luigi, and also has no qualms over leaving Hellenand her staff to their fates of being sucked up by Luigi's Poltergeist G-00 and be imprisoned despite the fact that Hellen was the one who freed him from being trapped in a frame. Professor E. Gadd describes King Boo as "the Master of Illusions".

Source

 * https://mario.fandom.com/wiki/King_Boo