Grim are the latest byproduct of the Chimera's conversion process and are created by using Spinners, which capture human hosts and weave cocoons around them. The cocoon slowly rebuilds the host as they are converted into Grims. A Grim has the appearance of a nude, sinewy Hybrid, lacking cooling units. Their spines appear to bulge out too.
The Grim's main form of attack is to rush at the player and engage in melee; this attack can be very powerful when in large groups. An average group can have up to twenty Grims. Surprisingly, they are tenacious creatures and can survive even if one of their limbs have been cut off (by a saw blade from a V7 Splicer or Rossmore 238 Combat Shotgun). They will crawl towards the player to attack if they have lost a leg, or hit the player with a severed arm.
Grims appear to remain in a hibernation state in their cocoons, until any unwanted intruder enters their proximity. Also, Grims seem to remain in an indefinite length of time in gestation, as that in Chicago a large Grim population remains in the city, even two years after it is conquered by the Chimera, there are still cocoons located around
Grims are among the Chimeran strains that are considered "feral". In appearances, the Grim have a red gash running from their neck to the middle of their chest and a less human-like skull than in Resistance 2, and are now larger, averaging eight feet tall; child Grims are no longer present, and even small Grim cocoons will hatch full-sized Grims. The strain shows some evidence of intelligence, throwing rocks or small debris at their enemy at unreachable distances rather than blindly charging. They are also capable of swimming.
Intel describes a Grim as a "half-baked hybrid," stating that Grims are hatched before they are fully converted.[[|]] It has never been made clear how a Spinner cocoon becomes a Hybrid, but according to this, Grims are actually an undesirable by-product of the process rather than its goal.
Grims are seen fairly routinely in Burning Skies from the level George Washington Bridge and onwards. As in other games they hatch from pods and attack in large groups, and are vulnerable to anything but slow-firing weapons. The Grims in the game have pale skin with red highlights, and a shiny look to their bodies as if coated in slime. Unlike Resistance 2 Resistance 3, Grims are created by the Crawlers.