Professor Arthur Hawkins, known as Arthur Hopkins in the Japanese anime, is the American best friend of Solomon Muto and the grandfather of Rebecca. His original Japanese name is kept in the English video games.
When Kaiba tried to buy Solomon Muto's "Blue-Eyes White Dragon" card, Solomon refused, saying it was given to him by a dear friend. In the manga and first series anime, a photo of Arthur and Solomon is visible as he says this.
He is briefly seen after Rebecca finishes her duel with Yugi; his major appearance is in the Waking the Dragons arc, where he investigated the history of Atlantis and of the Orichalcos. He gives information to Yugi concerning both of them and is instrumental in discovering the location of the lair of Dartz. He also appears during the Grand Championship arc.
Arthur is seen dueling with Yugi's grandpa during the flashback when Yugi and Rebecca, though not much of his Deck is shown. His Deck is similar to Rebecca's. He also has an Ancient Deck like Solomon Muto, but is incomplete.