Rigby is a grave robber hired by Professor de Montfaucon and an unnamed colleague in order to retrieve a powerful Null artifact.
A letter addressed to “Mr. Rigby” can be found in the first level of The Room Two: The Crypt. The author of the letter looks down on Rigby as a man of poor breeding and character and warns him not to attempt to use the artifact himself. The words “ENORMOUS VALUE” and “power” are emphasized in red pen on the letter, possibly by Rigby himself. This could suggest that Rigby ignored the words of his contractors and attempted to claim the Null.
Rigby’s name is referenced later in an easter egg. During The Seance, if the player enters the word “OTHERS” into the typewriter, A.S. (the voice of the typewriter) will list several names, one of which is Rigby’s, and decry that he should have encountered any one of them by now. This could mean either that A.S. has simply read of Rigby in passing and knows he is a traveler like himself, or that Rigby and A.S. had some closer association, maybe as members of the same research team.