SCAVs

The SCAVs are a neutral faction, operating covertly in the Suicide Forest as rogue soldiers. They're willing to do anything and help in any way for the right price, and they're currently led by Maska-Man. The only two SCAVs we've canonically met in the lore thus far are SCAV that took a piss and The Guy.

They patrol both the edges and the inside of the entirety of the forest, all of them being familiar with its ever expanding, confusing woodland layout. They have many hideouts throughout the forest, in which they sleep, eat, and discuss political views.

Appearance
In the present, it appears that the SCAVs have a less militarized appearance, as The Guy is the only SCAV we see in the present timeline, wearing no protective gear whatsoever, with even his pistol seeming like a flimsy toy.

In the past timeline, where we saw the SCAVs are under The Grunfeld's pay, they seem much more geared up and militarized, wearing green digi-flora uniforms, armor, balaclavas, and carrying actual lethal weaponry.

Suicide Forest 2: Electric Boogaloo
The only SCAV we see in this episode is The Guy, someone who eagerly accompanies and guides the crew as they trek on their journey through the forest.

Operation Peder: A Suicide Forest Story
In Operation Peder: A Suicide Forest Story, SCAVs have been shown to be led by The Grunfeld, who must've seemingly paid them a lot of money to either help guard him, or to secure his mission of revenge. The first SCAV that we see in the episode walks up to The Grunfeld, informing him that enemies have been discovered in the forest.

Another SCAV is later shown shooting at Lewko, hitting him in a non-lethal spot, only to be killed by Artyom when going to investigate the body.

Two SCAVs are later disposed by the group, one of them being the fabled SCAV that took a piss. He's killed as Lewko slits his throat, and the other is killed from a couple of shots from Artyom's weapon.

The final SCAV we see in this episode waits outside The Grunfeld's HQ, horrified at the sight of the Slender Man, threatening to shoot before he's quickly bested by the taller man.

Anatoli: A Suicide Forest Story
SCAVs are rumored to appear in Anatoli: A Suicide Forest Story, alongside the appearance of their leader Maska-Man.

Fun facts

 * All the SCAVs in Operation Peder were played by the same person, wearing the same costume, if that wasn't blissfully obvious enough.
 * The SCAVs seem to be immune to the effects of the forest, implying that they might be built diffrent.
 * The SCAVs actually have many diffrent sub-classes, including the SCAV Juggernaut, SCAV Driver, SCAV Guard, SCAV Raider and the SCAV Sniper. It is currently unknown which SCAVs were which.