Complex sentence: The 2003 film and the comics both follow the interpretation of the master of the house being Gracey, and merchandising for Disney Parks has since adopted the popular notion, identifying the Aging Man as Master Gracey on various "Haunted Mansion"-related items.
Split into simpler sentences: The 2003 film follows the interpretation of the master of the house being Gracey, as do the comics. Merchandising for Disney Parks has since adopted the popular notion, identifying the Aging Man as Master Gracey on various "Haunted Mansion"-related items.