Resistance: Fall of Man/Enemies

Chimera
Distinctive features: Beetle-like appearance
 * Crawlers: Crawlers are small beetle-like creatures used to spread the Chimeran infection. Though capable of limited flight, they are most often delivered by Spire missiles.  Upon finding victims, Crawlers penetrate their bodies, usually through the mouth and nose.  They inject the Chimeran virus and quickly expire.  The infected host falls into a coma as the virus begins the inexorable conversion of the host into a Chimeran creature. They are never fought in the game and are first seen when Sgt. Hale and a group of American soldiers are attacked and infested by a swarm.

Distinctive features: Small, quadruped, green tinge, tail with double tip
 * Leapers: Crawlers which fail to infect a host will eventually evolve into Leapers. They first seek out sustenance, such as human or animal corpses.  Once they have gorged themselves, they develop a protective pupae, a Leaper Pod.  They spawn from their pods upon maturation.  The voracious young Leapers attack opponents with teeth and claws.  They should be dealt with at range whenever possible.  Easily handled individually, Leapers are lethal in large numbers.

Distinctive features: Pulsating sack
 * Leaper Pods: Leaper pods are Chimeran eggs where Crawlers grow into Leapers. Their appearance is akin to that of a pulsating sack, rather than an egg. Leaper Pods will explode when vibrations are felt. When a Leaper Pod explodes, it releases the Leaper lying dormant inside. If they are undisturbed for a long time they will hatch automatically without releasing any Leapers. Leaper Pods still release swarms of Leapers when hit by a bullet.

Distinctive features: Human-sized cocoon, large orange spot on the front side
 * Cocoons: Once delivered to conversion centres, Chimera infection victims are enveloped in cocoons. Within each cocoon, a human body is broken down and recombined into a strain of Chimera.  It is theorized that multiple human bodies are required for the larger strains.  External measures must be taken to keep the cocoons from overheating.  This outside intervention suggests the conversion process is not being performed in ideal circumstances.  It is unknown if there is a more natural way for the Chimera to reproduce.

Distinctive features: Thin, found leaping from wall to wall (very rare to be found standing on two feet)
 * Slipskulls: Slipskulls are cunning opportunists who prefer to take pot-shots and make blind-siding attacks rather than face their opponents. With their speed and stealth they excel as scouts and ambushers.  Slipskulls scale walls and ceilings to gain an advantage on their prey, they resemble tree frogs that scale trees with their suction padded feet.  The discovery of a Slipskull requires immediate engagement to prevent them from summoning Chimeran reinforcements.  Explosives are the recommended response.  Hybrid Bullseye rifles and the Slipskulls' own Reaper carbines are also suitable and a single shotgun blast can take one down.

Distinctive features: Similar to leapers, only bigger and brown, can curl into a ball and use themselves as a projectile
 * Rollers: Rollers are adult Leapers. Their size allows them to bend their necks enough to reach the end of their body, turning themselves into wheels and allowing them to roll at a fast speed. Since they are near the end of their lifespan, some of their organs have started to decay, which allows them to spit toxic gases. To tell them apart from the younger Leapers, Rollers are larger, faster and have a brownish color.

Distinctive features: Carry Bullseye rifles, four pyramid-shaped cooling towers on back.
 * Hybrids: Hybrids are the most encountered chimeras in the game. They carry the Bullseye. Their appearance is mostly humanoid, although they have scales and their heads look like a ferocious lizard rather than human.

Distinctive features: Very humanoid in appearance except for the lack of a nose, ears and skin around the mouth, slow and unarmed. They use biting as the primary melee attack, and they can deal a considerable amount of damage if the attack connects.
 * Menials: Menials are workers of the Chimera and they are not bred for war. Even though they are labourers, they will attack enemies as soon as they see them. Their appearance is much more human-like than any other Chimeran strain. Menials are unarmed but dangerously volatile.

Distinctive features: Larger than Hybrids, carry large Auger rifles, single large circular cooling tower on back with a smaller one right behind
 * Steelheads: Clever, calculating, and extremely powerful, Steelheads are a superior variant of the Hybrid strain. Their heavy armour is usually seen at the forefront of battle as they lead Hybrids and Hardfangs into combat.  They willingly endure any punishment to advance the Chimeran invasion.  Steelheads wield the Auger rifle, a weapon which tunnels through walls, making their relentless attacks virtually unstoppable.

Distinctive features: Large shoulder armour, carry Arc Chargers, two large blocky cooling towers on back
 * Hardfangs: Hardfangs are more powerful forms of Hybrids. Any sense of self-preservation has been genetically removed. They are stronger than normal Hybrids and have larger fangs. Their bodies are heavily armoured. They carry the Arc Charger, making them very dangerous at close range. They exploit this by wading into the center of enemy platoons so as to maximise the damage they inflict.

Distinctive features: Larger than Hybrids, long arms and legs, outdated-looking cooling apparatus, unarmed, no armour, fast moving
 * Greyjacks: Greyjacks are old Hybrids who managed to survive for years. Because of their old age, they have outgrown their bodies and their cooling apparatuses are malfunctioning, causing them to overheat, and suffer necrosis. They are slimmer than the younger Hybrids, and they don't carry any weapons, possibly because their fingers have either lost their dexterity or have simply become too long to fit around a trigger properly. They use their sharp, dirty claws to attack, resulting in deep, difficult to clean wounds, and their lanky arms give them longer range than younger Hybrids. It is recommended to stay as far away as possible from these creatures.

Distinctive features: Six pointy cooling towers on back, more armour than standard Hybrids, quite slim
 * Advanced Hybrids: Advanced Hybrids are highly trained Hybrids. They require a much more advanced cooling apparatus, helping them stay at a cooler body temperature. The Advanced Hybrid's main purpose is to guard the Chimeran Towers where the Angels lurk. They are heavily armoured, much like the Steelheads and carry the Bullseye Mark II.

Distinctive features: Quadruped, dog-like, fast, unarmed, orange colour
 * Howlers: Howlers are a large quadruped strain of Chimera. Their rudimentary vocalizations are believed to provide the beasts with some level of communication.  Their calls can be heard for miles and have a chilling effect on those familiar with the source.  Howlers have a leathery hide that shrugs off most light-arms fire, although Combat shotguns at close range have proven highly effective.

Distinctive features: Jellyfish appearance, flying, never attack, invulnerable to attack
 * Carriers: Carriers collect infected humans from the battlefield after a Crawler attack. They ferry their catch to the nearest conversion centre.  As those infected bodies are also the Carrier's food source, not all of them survive to be converted.  Early in the Chimeran invasion of Britain, Carriers formed caravans hundreds of miles long.  It is unknown if the Carriers have found a new role now that fewer victims are available for conversion. They are sometimes seen in the sky, and can actually be shot by the player, but the attack will not cause any visible damage. As a side note, carriers closely resemble the "Tripod" described in H. G. Wells' The War of the Worlds, although they are not equipped with any armour.

Distinctive features: Very large, no armour, carry Stalker cannons, roar loudly, explode upon death
 * Titans: Titans are large Chimera. They have immense strength and carry weapons usually seen mounted on Stalker vehicles. They don't use armour due to their thick hide being able to resist small arms fire. Their heads and their cooling apparatuses are the only areas that have been proven to take a titan down faster, rather than shooting at their torso, legs or arms. They are thought to be created from several infected humans, and said to be the limit of power that the Chimera can reach before the human form is lost. Once enough damage has been dealt to the monster the player will hear an odd beeping noise coming from the Titan. This beeping will increase in temperature until the Titan's ammo pack on its back explodes, sending a wave of gibs (flesh and body parts) flying everywhere.

Distinctive features: Like a quadruped spider, spit explosive globules similar to Sapper mines
 * Widowmakers: The appearance of a Widowmaker on the battlefield requires immediate engagement by all soldiers. Widowmakers attack with their barbed fore-talons or by spewing explosive globules.  In addition to causing tremendous casualties, Widowmakers have a rallying effect on other Chimeran strains.  They have been known to irreversibly turn the tide of battle.  Attacks with high-explosives or vehicle-mounted weapons should focus on the creature's face or body.

Distinctive features: Flying, tentacled, throw toxic materials that emit lethal gas clouds, throw nearby debris with their tentacles.
 * Angels: Angels are belived to be the most advanced strain of Chimera. They command all Chimeras through a type of latent telepathy. Without the presence of an Angel, the Chimera would die. They are capable of attacking the enemy even if they are not used for war, much like the Menials. They attack with their tentacles, which they use to whip and throw debris, and by throwing toxic material that erupts into a deadly gas. First encountered when Sgt. Hale is sent a telepathic message from one of the creatures when he touches the container it is in, he receives these messages as he is part chimera because of the infection that was given to him by a swarm of crawlers.