My suspicions:
UNSC (Humans)brewersalliance
Insurrectionists
lilweirdward
Tony Maurice
The Warrior
KevinH
Wolfpacks
Office of Naval Intelligence
Finster Baby
Covenant
Ali bin Turban
Lyner
Alien Rebels
Robert2424
Ferastical
The Flood
Rafay
Canik
Forerunners
Torres951
captainjf
So is everything after Abt on there scum?
Gonna go out on a limb and say we don't have 7 scum in this game lol
In the time before the human race as we know it today, the Forerunners existed across the majority of the galaxy. Their plan to defeat the flood consisted of two parts, which could be executed individually if necessary.
1. Shield Worlds: Basically a small bubble in space (diameter of a tea plate) which contained a Dyson Sphere (Sun to Earth diameter, but concave to the sun) for the Forerunners to live in.
2. The Halo rings whos purpose is to defeat the flood. However, the rings were not designed to kill the flood, but to kill their food source consisting of all intelligent life in the galaxy.
There are several classes of Forerunners who had high positions in the lore, one of them being the Librarian who was a Lifegiver. Essentially, her role in the events that near and after the activation of the halo rings is what saved life in the galaxy. This Librarian collected samples of all sentient life in the galaxy in order to restart after the activation of the halo rings.
Why did I type all this? Basically to state that not all Forerunners are scum. Unless the Ur-Didact is a role in the game, I would assume any Forerunner aligned players are friendly.
I don't remember who said it above me, but I would assume roles to be:
UNSC
Covenant
There may be other roles and maybe even other alignments, but I think at this point in the timeline the only Scum would be Covenant. MK was a Covenant Elite, basically super strong soldier type.