Many of the Paragon's shouts from Nightfall can be related to pop-culture references such as "Can't Touch This!" "It's just a flesh wound." and "The Power Is Yours!"
Verata's name probably comes from clatto verata nicto, the incantation that Ash repeatedly fails to recite correctly in Army of Darkness, which is, in turn, a parody to the command klaatu barada nikto from The Day the Earth Stood Still.
Shiro Tagachi's first name in Japanese term refers to someone who is "overly stubborn, perversely unyielding, or intractable".
The Great Northern Wall is highly influenced by The Wall in George R. R. Martin's series A Song Of Ice and Fire, both being great walls built and expanded over many generations of kings.
Rurik's name means 'famous ruler' in Old Norse. Prince Rurik may be named after Prince Rurik of Novogorod, the first Varangian ruler of Kievan Rus', and the founder of Russia's first royal dynasty. Ascalon was even called 'Kiev' in some old beta screenshots.