The DenOfGeek site has an article on Ash Vs Evil Dead at Comic Con and they revealed Ruby’s surname.
“That was straight out of the 1950s,” remarked Lucy Lawless, who also is in the series as Ruby Knowby (relative of the original Evil Dead Trilogy’s Professor Knowby).
For those unfamiliar with Evil Dead:
Professor Raymond Knowby is Annie Knowby's father and Henrietta Knowby's husband. He traveled to the Cabin to finish his research on the Necronomicon. However, things turn out very badly when he recites a passage from the book releasing the Evil from "Hell". He is attacked by his possessed wife and is forced to lock her in the cellar. Before succumbing to the Evil himself, he manages to leave a tape explaining the terror he has unleashed and manages to trap the Evil within the woods around the Cabin (how he does this is unknown), then later shows up as a spirit explaining to his daughter Annie on how to get rid of it. In The Evil Dead, his voice was performed by Bob Dorian and was personified by John Peaks in Evil Dead II. Source
Find out more about Lucy's new role as Ruby in Ash vs Evil Dead by going to the AUSXIP Lucy Lawless Ash vs Evil Dead Subsite