Though the Master Chief is Halo's biggest star, he's far from the only beloved character in the Sci-Fi universe. Over the course of just over two decades, the Halo franchise has amassed quite the compelling cast of side characters, ranging from Halo 3: ODST's titular gang of shock troopers to classic staples like Sgt. Johnson to some lesser-known heroes like Halo Wars' Spartan Jerome-092.