MadBrok
Isaac Clarke manages to fend off the reanimated Necromorph version of his wife in his shuttle, and locks her in a toilet or something. (Year 2501). After making sure the necromorph is secure, Isaac prepares for cryo sleep (let's imagine the shuttle is equipped with it, there is a cryo bay on the Ishimura at one point), and enters it. Fifty Three years later (2554), after drifting trillions of miles, the power cell of the shuttle's cryo sleep is finally depleted, and Isaac awakens, the necromorph secured in the bathroom still. Immediately Isaac scans for any shuttles or ships, and gets a signal approximately twenty thousand kilometers away. This ship is the half that Cortana and Master Chief are stranded on, and Isaac (still ignorant to this) sets course for the vessel. Isaac docks the shuttle and enters the ship, only to be contacted by Cortana etc etc, Master Chief is awoken. Isaac returns to the shuttle to find that the necromorph has finally figured out how to escape, and aims his Plasma Cutter into an empty room. He hears crashes in the adjacent room, and enters to find Master Chief in ready stance, and a gaping hole in the roof where the necromorph has made it's escape, presumably in search of other life forms. Little did the chief know that a new, growing gravemind had been forming in the engine room of the remaining ship. Said Gravemind takes control of necromorph, and gains all knowledge on how the necromorph species operates. Master Chief (with Cortana) and Isaac Clarke make it to a secure room on Isaac's shuttle before they can be overrun with Flood Infection and Pure Forms and the Necromorph. Gravemind reforms on the hull of the shuttle, and dispatches Flood to set a course to the nearest human colony. The Flood, Master Chief, Isaac Clarke and Cortana all arrive on the shuttle, with the Flood now utlizing new Necromorph contagion filling half of their infection forms. The colony is quickly overrun and infected, crawling with Necromorphs (lurkers, leapers, slicers, brutes) and Flood (combat, ranged, bursting, tank) alike, and Isaac, Master Chief and Cortana must work to obliterate the threat. So can master chief and Isaac clarke prevail against an incredibly OP'd enemy; coordinated necromorphs and flood all controlled by a growing gravemind?