Everybody gangsta til the precursors get a little hungry.

Hi again, been a while since I've posted, been sitting on this idea for a while for you guys. :>

For those unaware of the halo franchise's resident zombie faction, the Flood is a parasitic hivemind, single-mindedly consuming everything in the universe until all is Flood. Here's a rundown of the odds you're up against.

All Flood forms share a single consciousness, which becomes progressively more intelligent and sophisticated with every sentient host that is assimilated. When enough hosts have been infected, the Flood consciousness becomes a Gravemind - a self-aware, highly intelligent entity that strategically commands all Flood forms in an outbreak. Due to this group consciousness, the Flood as a whole is more accurately described as a single, transsentiant superorganism rather than a collection of individuals directed by one or more controlling beings. In the absence of a Gravemind, the Flood possesses only basic coordination; they are incapable of forming complex strategies, and focus solely on attacking and infecting nearby sentient organisms. This stage of a Flood outbreak is known as the Feral Stage. At this stage, the Flood seek to create an assembly of biomass, calcium, and nervous system reserves, which leads to the creation of a Flood hive and the beginnings of a Proto-Gravemind. The nature of the Flood's collective consciousness is similar to that of a hive mind, the Flood act as a unified entity, with no individuality that is inherent to other species; each vessel of the Flood works tirelessly to aid in the propagation of their species.

The Flood presents a highly variable and unconventional threat in combat, as it can infect and mutate dead or captured opponents into a myriad of deadly forms, effectively growing stronger as it weakens enemy forces. They are widely considered to be the greatest threat to the existence of life (or, more accurately, biodiversity) in the galaxy.

Now with that background covered, here's a little about the scenario.
Who are you?:
Who knows? It's left open for you to decide whether you're a marine, civilian, or even a xeno!
Where are you?:
You'll begin in an urban center, but feel free to decide what planet or just tell the bot "alt start".
When are you?:
I set it to assume the year is 2552, but it won't be directly stated so go wild!
What stage is the invasion in?:
Just so you're not entirely screwed from the start, this is the first instance of a flood outbreak on this planet. Word hasn't gotten out yet, but the Flood's numbers are yet to swell to a tipping point.

Have fun!