Professor Elvin Gadd, often shortened to Professor E. Gadd or simply E. Gadd, is the scientist first appearing in Luigi's Mansion and founder of Gadd Science, Incorporated. His name comes from the archaic exclamation "egad," something that one says in surprise or anger. He is roleplayed by JeloJellyJam.


Pre-Locked Rooms

He used to live on the foothills of the Thwomp Volcano. The Mario Bros. go back in time and end up saving his lab from burning down when fire blocks erupted from the Thwomp Volcano. He then helps the Mario Bros. by inventing the Hydrogush 4000. Although he doesn't directly invent the Hydrogush 4000, his older self does in a complex way: Young E. Gadd starts to get an idea after a totally unrelated event happened during the present time, which transfers to his future self, causing the present-day, elderly professor to send water from the Hydrogush 4000 via Time Hole and calm the erupting Thwomp Volcano. After all this excitement, the twenty-year-old E. Gadd moves to Boo Woods.

Many decades later, Luigi enters the mansion and is saved from ghosts by a strange old man wielding a vacuum cleaner. Professor E. Gadd reveals he lives in a house near the mansion, where he researches his favorite subject: ghosts. Luigi explains his brother Mario is missing within the house, and the professor decides to help Luigi by giving him two of his inventions, the Poltergust 3000 and the Game Boy Horror. The professor continues to help Luigi, giving him help and tips.

E. Gadd takes up residence in Evershade Valley after learning that the ghosts there are friendly. Eager to examine ghosts without fear of being attacked by them, he sets up a laboratory in the Gloomy Manor and a Bunker close by the mansion. There, he begins researching the ghosts of the five mansions that populate the valley, and sends his five Toad assistants to the other four mansions in the valley to examine the ghosts there. At first, the resident ghosts welcome him and assist him in his lab, but when King Boo arrives and destroys the ghost-pacifying Dark Moon that hangs over Evershade Valley, the ghosts start running amok and destroy E. Gadd's equipment. He flees to his nearby Bunker and enlists the help of Luigi to help rebuild the Dark Moon and calm the ghosts once more.

E. Gadd actually never went to the Rooms by door, but by using an invention of his, the Multiversiporter 2000, after hearing that Luigi, Mario, Peach, Daisy and countless others were trapped in the multiverse.


Professor E. Gadd is an eccentric yet intelligent inventor. He has made a lot of successful inventions. He is usually friendly to the gang.


  • Glasses with swirls are often seen in Japanese media that are a feature E. Gadd shares with Professor Frankly, Fawful, Francis, and Iggy Koopa.
  • He is one of the few Mario characters to not be voiced by their original voice actor, the other being Yoshi with the translator.
    • The reason for this was that his roleplayer liked Brentalfloss' impression of E. Gadd in Luigi's Mansion with Lyrics and Luigi's Mansion: Dark Moon with Lyrics, and because he was going to speak English rather than gibberish.

Character Info

  • E. Gadd has actually met Jelo, Gerry, Peeter and Rosewell back then.
  • So far, E. Gadd had made two horrible problems happen by accident.
    • He gave Bowser Jr. as Shadow Mario the Magic Paintbrush, thinking he was Mario.
    • He sold King Boo's portrait in a garage sale, which unleashed him by accident, leading to the events of Dark Moon.
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