Complex sentence: Khelben "Blackstaff" Arunsun, Lord Mage of Waterdeep, is a fictional character of the "Forgotten Realms" "Dungeons & Dragons" campaign setting, brainchild of "Forgotten Realms" creator Ed Greenwood and Realms game designer Steven Schend.
Split into simpler sentences: Khelben "Blackstaff" Arunsun, Lord Mage of Waterdeep, is a fictional character of the "Forgotten Realms" campaign setting for the "Dungeons & Dragons" fantasy role-playing game. Khelben is the brainchild of "Forgotten Realms" creator Ed Greenwood and Realms game designer Steven Schend.