Marked men are hardened ghouls with a fiery red color, their skins peeled off by the violent storms of the Divide. Because of this, their skeletal muscles are exposed, giving them their red appearance. They are considered ghouls, in that the intense radiation of their surroundings is keeping them alive. To protect their new skin (or more likely, themselves), they continue to wear tattered clothing from their respective factions. They maintain their clothing from scavenged pieces of scrap, such as fallen road signs, license plates, and other bits of metal. In order to feed themselves, marked men have resorted to cannibalism, evident in the hunks of human meat and flesh found nearby their encampments.
Marked men level with the player, have a high amount of health for humanoid opponents, and are moderately protected by the tattered armor they wear (albeit far less than properly maintained regular versions of their armor). They are overall on par with the White Legs tribals of Zion Canyon, and the lobotomites of the Big MT, in terms of health and armor.
They carry a variety of powerful melee and ranged weapons, and at higher levels (above level 40) have the unique attribute of being the only faction that almost universally uses non-standard ammunition for their weapons (i.e. slugs and armor-piercing rounds), increasing their combat proficiency against well-protected targets. Additionally, many marked men make simultaneous use of both firearms and grenades. At times, they can be found using Stealth Boys, making them harder to detect.
When near sources of radiation, they regenerate health rapidly, even more so than ordinary ghouls. However, they tend to be few in numbers, and it is rare to find more than a dozen in any particular location, unless the player is a high level.
They wear either マークド・トライバルアーマー or marked patrol armor, suggesting that they are a mix of former NCR rangers and former high-ranking legionaries. As such, they are slightly better protected than lower-ranking marked men.
Irradiated heavy troopers are the ghoulified remnants of NCR heavy troopers stationed at the Long 15 outpost. After the Courier launched the nuclear missiles from the Divide at the outpost, the radiation left behind turned them into ghouls, leaving them hostile to all others. They look like regular NCR heavy troopers with the added ability of regenerating health while irradiated.
The marked men that appear during the final battle will explode after being killed, with an explosive effect identical to that of a plasma grenade. This was done to prevent lag from too many corpses being in one area. It is still possible for it to lag by killing multiple marked men at close range with weapons like the shoulder mounted machine gun or frag grenades.
The Marked men are some of the few enemies in the game that will use special ammunition against the Courier.
If affiliated with the NCR, the player can comment to Ulysses that many of the marked men appear to be NCR special forces (more specifically, rangers or other special combat teams). A Legion affiliated player can do the same, noting that several marked men were Legion scouts, assassins or Frumentarii.
Former NCR marked men seem to have lost their dogtags.
Although female NCR troopers appear in abundance in the Mojave, there is no female variant of NCR marked men in The Divide or even the Long 15.
An additional, unused variant of the irradiated heavy trooper exists within the resources of Lonesome Road. Also called "irradiated heavy trooper", this version differs primarily in that it uses the default SPECIAL statistics for NCR troopers - 5 for all statistics. It also is equipped with a Minigun loaded with 5mm AP rounds, rather than the random weapon selection found in the standard version. Internally this version has the Editor ID NVDLC04NukeNCRColonel, indicating that this may have been an early stand-in for Colonel Royez.