Ever thought that the Biters, despite sometimes having HUGE populations, never have any in-fighting? Ever thought they were way too cute and cuddly and friendly with eachother? What about their farts causing pollution huh, haven't you heard of Global Warming?
Well, this mod changes all that. The biters have had enough of eachother, and have split into 5 warring factions, each vying to kill one another and take over the world (literally). Given enough time (and you should have biter expansion mechanics cranked up for maximum effect) ultimately one faction will have expanded and wiped out all others.
HOW IT WORKS:
On world gen and new chunks generated/discovered, the biter nests will be assigned factions for each "chunk", and large nests will have different factions within the nest - this causes small scale civil wars to break out until one faction wins and begins to repopulate and expand into the free land.
The biter factions will regularly (with some random variation, but more often as evolution % gets higher) send attack waves to nearest enemies, which includes other biter faction nests, or the player's base.
If you want you can play with the values in the control.lua at the top to modify the period between attacks or the attack % chance.
I feel this mod adds to the ambience of Factorio, makes it more interesting without having too much direct impact on the player either. It does make exploring into new areas (if you move very quickly) safer, because they will be busy fighting each other and then wounded after the fight if you get there soon enough.