'Halo' synopsis/important characters

Halo is a great game made by a company called Bungie. It is a first person shooter with online multiplayer. The single-player campaign is set around the year 2550A.D., when humanity is fighting a losing war against a collection of alien races known as "The Covenant". You play as a cybernetically enhanced human super soldier known as a "spartan", this spartan's name is name is "john-117" or "master chief". Shortly after starting the game you are introduced to "Cortana", a computer A.I. construct. Later, you discover an alien parasite known as "The Flood" which seeks to consume all life in the galaxy. Then you are introduced to "343 Guilty Spark" another construct, but made by an extinct race known as the "forerunners". 343 Guilty Spark (a.k.a. "spark" for short) looks a lot like a very large, floating, blue, night light and always seems to fly off to fix one thing or another right before you get swarmed by about a hundred flood, he also talks to himself all the time. I think this is a great P.C. game.