Ground Zero

The Cybernetic Evolution's opinion of mutants probably isn't much better than their opinion of humans. This is probably a scouting force to assess the defenses and resistance level here, well to hell with that you aren't going to let them report shit. You immediately open fire. You kill the smaller one in the center with relative ease, but the others go into battle mode and start laying down the firepower. You nearly get yourself killed before managing to take cover.

Other mutants hear the sounds of battle and rush to the area to help you, and soon the metal interlopers are a pile of sparking scrap.

"What the hell, you find new enemies for us?" one of the mutants asks you.
"Nah, I don't think we'll be having any more problems with them. They're busy with a war with the Combine; I doubt an army of cyborgs will be coming here anytime soon. Better go report this to the Captain though."

Soon after the cyborg diversion a lot of rumors start flying around that the Cybernetic Evolution will be attempting to invade Zeropolis or even that they've somehow allied with the Shadow Horde, but none of these rumors even come true. Though it does make Captain Salazar paranoid enough to take the current war with the Shadow Horde more on the offensive, of course this doesn't pan out too well.

When Salazar starts sending troops into the actual sewers they're at a severe disadvantage and the losses on your side are terrible, yet the Captain insists on carrying out this plan.

A few years go by and the Dust District's defenses are nearly completely destroyed. You're one of last defenders left and the Zeropolis Guard no longer exists as you know it. After Captain Salazar was struck down by an assassin the organization dissolved and it just became a bunch of armed mutants trying to defend their homes.

It's a futile endeavor though the Shadow Horde is relentless and as much as you might hate it, you have to leave; it's just simply not safe to stay where you are anymore. The question is where to go?

There are probably other places in the City where the Shadow Horde isn't as strong or even in control, but that might just be a temporary solution and it might not be any safer. The only other option is to leave the City which is certainly going to be dangerous as you know mutants aren't looked upon too kindly.