4. Halo
Microsoft's perennial breadwinning game franchise, Halo, got started on its EU almost as soon as the game debuted on the first Xbox. Eric Nylund's The Fall of Reach was great read and prequel, giving readers lots of information about the Halo setting, fleshing out the paper thin characters of the game, and making the universe feel like it had unlimited storytelling opportunities. William C. Dietz's The Flood was pretty typical of a game novelization, although the new subplots he added helped make up for his fact errors and how boring the main plot was. After the First Strike novel, which filled the gap between Halo and Halo 2, the Halo EU started slowly expanding into comics. But it wasn't until Contact Harvest that things started to get ridiculous. Halo always had a degree of ridiculousness like a military capable of building starships and advanced AI using bullets from the Vietnam War and the UNSC not realizing it could stick its tiny fusion reactors on old exoskeletons but Contact Harvest took it to a whole new level, introducing a miniature gauss cannon that is never used anywhere else and introducing items from Halo 2 and 3 in a story set over twenty years earlier. The Halo EU jumped even higher over the shark when it allowed Karen Traviss, an infamous Star Wars novelist, to write a series of Halo novels. One of her first acts was to recast Catherine Halsey, the morally conflicted creator of Spartans like and including the Master Chief, as a criminal loathed by all her associates (including the man she hired to train the Spartans) and anyone who wasn't one of her Spartans. Then she made the Office of Naval Intelligence, the recurring unscrupulous spies of the Halo universe, give weapons to one faction in an alien civil war the faction that hated humans, instead of the one led by an alien who fought beside Master Chief and wasn't going to attack a nearly extinct humanity. If some of this seems familiar, that's because Karen Traviss helped write Halo 4 and made this insanity canon. But the most ridiculous aspect of the Halo EU is the Forerunner Saga. Written by Greg Bear, an acclaimed science fiction writer with a long list of works to his name, the books are essentially a showcase of how powerful the guys who made the Halos and Ark were. However, there's just one problem for some reason, there's a highly advanced civilization of humans that are more powerful than the Forerunners. Keep in mind that these events are set 100,000 years before the events of Contact Harvest (where the humans and Covenant started their war), which means that 343 Industries (the guys who are running Halo now) thought it was a good idea to rip off Stargate (complete with the "second evolution of humanity" thing). Ultimately, the Halo EU has turned a somewhat entertaining setting and premise into a convoluted mess of incompetence and stupidity that sours the experience of playing the actual games.