Ceph

The Ceph, short for Cephalopods, also known as the Charybdis, are a technologically advanced alien species who arrived on Earth approximately 65 million years ago, and represent the primary antagonists of the Crysis series. They are hostile towards humanity and are waging what appears to be a war of extermination against them. Although there are several theories, it is speculated that they have been acting to prevent human degradation of the Earth's environment.

The Ceph on Earth originate from the Triangulum Galaxy, also known as "Messier 33", located in the constellation Triangulum, approximately 3 million light years from Earth. Their most recent activity prior to the events of the series occurred some 2 million years ago, after which they went into a dormant state until 1919, when Jacob Hargreave set in motion events in Tunguska that led to the eventual awakening of all Ceph lithoships across the Earth, though this began with minor activities and technology testing in early 21st century until their complete awakening by the Korean People's Army on the Lingshan islands.

Overview

The true origin and age of the Ceph is completely unknown. The earliest record on them is that they arrived at the Solar System 65 million years ago along with multiple space vessels/seeding ships with unknown purpose (though the one on Earth is similar to a scientific outpost). The seeding ship found on Earth is thought to be the cause of the mass-extinction event at the time, and it was rendered inactive for an unknown period of time before becoming active again, gathering energy along with other Ceph devices across the planet to form a network.

Their purpose is also expanded upon in the novel Crysis: Legion. Jacob Hargreave speculates that, since the Ceph have such advanced technology that can create practically anything they can think of, their sole interest is in the things they can't think of, namely surprising proteins and organisms that evolution gives rise to over millions of years of adaptation. If this is the case, then the Ceph stationed on Earth are only an automated system programmed to wake up every once in a while to scout the planet for scientific data that might be useful.

According to the Gardener Theory speculated by Hargreave, the Ceph on Earth might be "gardeners" that look after a "garden" (Earth), nurturing its life and observing evolution of all lifeforms on it. Their fight with humanity is in fact, similar to how a gardener trying to cut weeds, or the owner of a house (Earth) finding bugs in their home. This came from when the Ceph awakened and soon found out that humanity is slowly destroying the Earth, making their work that spanned many millions of years gone to waste.

After the capture of Alpha Ceph, when C.E.L.L scientists spent 20 years cracking their communications and studying them, they came to the general consensus that the Ceph and their language were so far beyond the understanding of humanity that most of their work is all but speculation, leading them to underestimate much of their Ceph-derived technology. However, though, they were able to gain some vital information on the unimaginably more advanced extragalactic Ceph from the Triangulum Galaxy.

It is known that the southern spiral arm of the galaxy is a part of a vast, billion-year-old web of countless planets, ships and colonies that make up a single over-hive called Hyperion. Two much smaller but still immense over-hives existed in M33 Galaxy is Iapetus to west of galactic core and Coeus at the eastern fringes and another one million additional hives, each covering three or more star systems. The age of Hyperion suggested that it might have been another seeding ship from a more ancient Ceph, as the entire M33 Galaxy Ceph is only half a billion years old while Hyperion is one billion years old.

History

The Ceph have been on Earth for at least 65 million years, and are implied to have seeded Earth with the basics of an ecosystem. They left behind infrastructure that would periodically awaken and study that ecosystem for unique proteins that may have evolved. For most of human history, they laid dormant - even after Jacob Hargreave and Karl Ernst Rasch triggered a catastrophic explosion in one of their facilities in Tunguska. Only in 2020 did they fully awaken in response to American and North Korean forces tampering with another facility under the Lingshan Islands. This is the first Ceph Colonization Stage, before they had become adapted to the "new" Earth humans had created. Through the events from Crysis 2 the Ceph begin to adapt to the Earth triggering Ceph Colonization Stage 2. Through the events from Crysis 3 the Alpha Ceph opens a Einstein-Rosen Bridge to their parent galaxy in order to bring their main invasion force to eradicate all humans, known as Ceph Colonization Stage 3.

Crysis

During Crysis, the Ceph (though not referred in name) were first "officially" discovered in the Lingshan Islands by a CIA-tracked archaeological expedition led by Dr. Rosenthal, who had unearthed fragments of their technology in other parts of the world. Subsequently, the North Korean government became aware of the alien technology and dispatched the Korean People's Army to secure the Lingshan Islands in an attempt to appropriate it. In turn, the United States, after being urgently contacted by Dr. Rosenthal, also sent American military forces backed by the USS Constitution, USS Lexington and USS Maine carriers group in for a rescue mission and to prevent the KPA from acquiring the artifacts. Inevitably, the Koreans under General Kyong succeeded in activating the structure (which Kyong called a "temple") and inadvertently awakened the Ceph, who shortly thereafter deployed an "ice sphere" which flash froze most of the island and killed everything that was within range.

Robotic Ceph forces overwhelmed American and Korean forces remaining in Lingshan, forcing them to evacuate. The United States sanctioned a limited nuclear strike against the ice sphere, but instead of dispersing, the sphere absorbed the nuclear explosion and expanded, prompting the Ceph to send a massive counterattack that sank the entire U.S. carrier group (Constitution and Lexington sunk by Ceph Warrior and Maine is frozen by the Ice Sphere).

The Lingshan Ceph were composed of almost entirely robotic units or heavily armored weaponized "exoskeletons". Weapons seemed to follow a pattern of ambient energy absorption: practically all units had the ability to drain nearby energy sources be it nuclear and electrical, and more direct weapons came in the form of freeze rays and high-powered icicle launchers, as well as energy-based explosives and more "traditional" energy beams.

Crysis comic

During the Crysis comic, the bipedal Ceph exoskeletons used in the New York Incursion 2 years later seem to be available on Lingshan as well. However, the tentacles are black and the armor seems be slightly different than what's seen in New York. Other variants are also seen, such as a small drone-like walker that can shoot down a VTOL with a single shot and a giant bipedal exoskeleton several times taller than a human. There are also living tentacles inside the alien ship, which no longer have an anti-gravitational field. The ice sphere is notably absent in the comic, though it is possible for it to be simply out of view. On the other hand, a carrier fleet is headed towards the island to rescue the now destroyed carrier fleet on Lingshan Island, as well to prevent the Ceph from advancing any further.

Crysis 2

The Ceph in Crysis 2, which still relate to the aliens from the original games, appear to employ different strategies and technologies than the group at Lingshan, as well as having a different morphology. They seem to have gone so far as to actually mimic human combatants, relying of more "conventional" forces such as dedicated infantry, armor and air units. They have replaced their hovering trooper automatons with cybernetic soldiers composed of what appears to be an alien being encased in a suit of armor that grants it mobility, agility, great strength as well as a diversity of weapons. These weapons appear to function via some kind of projected energy; however they might as well be a sort of projectile, since they are referred to as "shells" in Crysis: Legion.

These soldiers come in Grunt, Stalker, and Heavy classifications, as well as some Command variants. Their Hunters and Scouts have been replaced with huge, heavily-armed tripod tanks known as Pingers, and gunships armed with missiles and rapid-fire weapons that mimic human military helicopters. Troop deployment is done via the use of specialized dropships, to transport and deploy troops via drop-pods.

The Ceph that emerged from underneath New York City also deployed what appeared to be a weaponized plague against the inhabitants. This "spore" was invariably fatal upon even the most limited contact, and was generally deployed via massive mechanical "spears" that emerged from underground, disseminating a thick cloud of nanite-viruses into the air. Crysis: Legion, however, reveals that the "Manhattan Virus" functioned as far more than a bioweapon for the aliens. Most of their technology was covered in receptor proteins for the spore; it is described as an "antibody system" that makes a desired area of the Earth suitable for alien habitation by eliminating hazardous macrofauna (humans), and the Nanosuit 2 was eventually modified to re-program the spore to attack the alien biology.

Crysis: Legion

While the events of the Ceph in New York City largely remained the same to the game, further details on the Ceph and the post-Crysis events are extended on, such as the Ling Shan islands being "glassed" by a superweapon and the carrier fleet that was sent to the island and the Ceph on it have "vanished" without a trace. Three months prior to Crysis 2, the lithoship in NYC begins to awake, causing not only the east coast of the USA but the entire continent of North America to suffer strange and large-scale weather events. The Ceph only start to begin activity only from day 23, before that they were collecting human biomass to create new Ceph units while still observing human activities. The perfected nanite-virus is named "Nano Spore", the Central Park spike tower is a terraform engine of the lithoship beneath the NYC and what it released is a mass-produce of the "Nano Spore" which has the power to destroy not only the tristate area, or the USA, but also the entire planet.

Crysis: Escalation

Few mentioned about the Ceph except some info on them during the Human-Ceph Global war. At some point in 2024, the Ceph occupies London, which forced UK Navy to destroy south London and the city to stop Ceph's incursion. In 2034, C.E.L.L finished their construction of Nanodomes on NYC and begins to build many others on former Ceph-occupied regions, after the destruction of the HMS Hood. Chino, Earl and Hank managed to escape C.E.L.L only be ambushed by a group of Ceph Stalkers. Earl and Hank are killed by the Ceph and Chino is rescued by Dane.

Crysis 3

After the events in Crysis 2, Ceph from the various hideouts across the globe attacked humanity in many countries. Some quickly fell to the Ceph, and even after the deployment of the modified nanite virus/Nano Spore and Archangel, the Ceph were too persistent and overwhelming to be defeated. C.E.L.L made their last push at Tunguska to capture the Alpha Ceph. Once they had they had it, they used it to harvest for energy C.E.L.L. The Ceph, having lost the guidance of the central hive-mind, largely reduced their activity and some, like the Stalker units, reverted to their almost animalistic behavior. Most of them entered dormant state due the lack of energy and many lithoships were "neutralized". Such inactivity led humanity to believe that the Ceph threat is over.

At some point, C.E.L.L researchers and scientists began to crack the Ceph's communication and began studying them. Along the way, they learned about the other Ceph and the ancient M33 galaxy hives, as well as the true nature of the Ceph's activities. This finally revealed that the Ceph are staging a planetary colonization process for Earth.

The Ceph colonization process takes place in three stages:

Stage One as explained in the comic are units largely reliant on the mothership for energy, meanwhile techno-organic units fan out to harvest energy - any and all kinds - to give birth/create/awaken a central intelligence, the "Alpha Ceph," while establishing and securing their territory or "sensitive area". With the nuclear strike in Crysis, the Alpha Ceph came to being, and the Ceph proceed into Stage Two.

Stage Two Ceph, as seen in Crysis 2 and Crysis 3, are no longer as reliant on the mothership for energy supplies, with their units largely adapted to deal with local environment and native species' resistance. Such learning and adaptations goes beyond exoskeleton and platform designs, but devices that are tantamount to those being used by the local species, like auto turrets and "smart" landmines.

Prophet would unwittingly release the Alpha Ceph from its confinement, resulting in the dormant Ceph awakening and destroying everything in their path. Within hours, both C.E.L.L and Resistance forces suffered heavy casualties. Hundreds of C.E.L.L operatives were reported to be killed and the Resistance is quickly overwhelmed and scattered across NYC. The Nanodome is destroyed, and all Defense Towers are neutralized. C.E.L.L. responded by sending in reinforcements but were unable to stop the Ceph. C.E.L.L. was forced to use Archangel to vaporize New York, though the plan was foiled by Prophet, Psycho, Claire and Karl Rasch (who was under Alpha Ceph's control).

The Alpha Ceph (through Rasch) revealed its plan to commencing Stage Three: By using its immense energy supplies, it opens and maintains a wormhole in the planet's orbit. This wormhole is connected to the Ceph's homeworld in the M33 galaxy, and from there come their warrior caste - Ceph dedicated purely to warfare - to completely annihilate any and all species that stands in the their way. The Alpha Ceph itself appeared and used Rasch to pin down Prophet, and Claire was mortally wounded while shielding Prophet. Psycho shoots Rasch and gets the group moving. Rasch, released from Alpha Ceph's control, told the group to escape before the Alpha Ceph finished him off.

Prophet ultimately killed it in battle inside the NYC lithoship, resulting in all the Ceph being disintegrated. However, the Ceph from the M33 galaxy managed to make it through the wormhole. In orbit, Prophet commandeered the Archangel defense satellite and used its energy beam to shoot at the massive Ceph warship coming through the wormhole, destroying it. The warship's subsequent detonation closed the wormhole, and ended the Ceph invasion for the time being.

Physiological

Ceph possess many similarities to Cephalopodic species of Earth, primarily their tentacle like appendages and boneless like body structure. Their skin is blue and seem to thrive in low gravity environment. Though they share many physical similarities with the Cephalopodic species of Earth, the Ceph are actually a hive species like ants, and share a single collective intelligence, rather than an individual, human intelligence. Their intelligence is vast, but they are so utterly different from humanity in terms of how that intelligence functions and how it manifests itself that the Ceph can be difficult for a human being to even comprehend. Though it may seem counter-intuitive to us, the Ceph have become so very successful by being a reactive species. While human civilization is built upon knowledge being steadily passed on from generation to generation, each new Ceph hive begins with relatively little inherited knowledge from its parent hive, but instead has a deadly ability to adapt and react - and react fast. It is this ability that makes the Ceph able to succeed and thrive in a billion unimaginably different environments - from earth-like planets, to high gravity gas giants and ice spheres, or the unimaginably hot, the unimaginably toxic and the unimaginably strange regions of dark matter and warped space-time, where our rigid human thinking would at best be useless, and at worst send us mad in seconds. The human brain may have evolved to dominate one specific planet, but the Ceph hivemind is engineered to dominate an entire universe.

Some Ceph, like the Alpha Ceph, have a psychological ability to control people, as seen with Laurence "Prophet" Barnes, Karl Ernst Rasch. The Alpha Ceph had a physiological and/or telekinetic power greater than the Mastermind.

Technology

Ceph possess highly advance technology which helps them to adapt to any possible environment. In Earth's case the Ceph created exoskeletons to better adapt to Earths gravity.

Military

Crysis

The Alien army encountered at Lingshan consisted almost entirely of autonomous or semi-autonomous machines, most of them making use of a kind of anti-gravity technology to fly through the air. They make use of ice- and energy-based weapons, and are capable of draining energy from almost any nearby source in order to power and repair themselves. The only biological aliens seen are inside the main alien structure.

Suit-less Ceph - The Alien creatures encountered inside the mountain structure.
Alien Trooper - small Alien robotic infantry unit.
Alien Scout - A highly maneuverable flying Alien machine.
Alien Hunter - A large four-legged Alien machine armed with multiple weapons, making it highly dangerous. The one seen in Crysis is protected by an impenetrable shield, while others, seen in Warhead, are more easily defeated.
Alien Warrior - A massive and heavily armed Alien warship.
Alien Spaceship - The massive Alien construct from which all the other Aliens come from.

Crysis Warhead

Guardian Trooper - A small Alien unit used for shielding generic Troopers.
Leader Trooper - Alien unit equipped with MOAR, plays a leader role.
Orange Scout - Flying Alien unit serves as a bomber.
Container Scout - Alien unit that did not self-destruct, kept in a container designed for nuclear warheads.
Red Hunter - Large 4-legged Alien used as heavy assault unit; appears to be a more heavily-armed variant of the "regular" hunter.

Crysis 2

The Ceph troops somewhat resemble the Suit-less Ceph from the first game and appear to in fact be them. It would seem that they have begun to adapt to the gravity of Earth through the use of armored exoskeleton suits. This allows the 'leg-less' alien to move about freely in an environment they are not adapted to. They wear a sort of mask, or helmet, that covers their "face". Their weaponry is built into the exoskeleton and cannot be picked up by the player. Most "humanoid" Ceph also have some kind of sharp claw mounted on one of their arms. They also seem to have replaced their cold-based weapons technology with what appear to be plasma weapons, as well as a semi-biological "spore", which seems to serve the same area-denial role as the ice sphere at Lingshan.

Ceph Combat Units, nicknamed Grunts. They are fairly tough opponents with moderate armor and reduced mobility. On the battlefield they take cover and return fire to their enemies.
Ceph Devastator Units, nicknamed Heavies. They are currently the largest and most durable of the Ceph infantry. On the left arm they are equipped with an X-PAC mortar, and the right is equipped with a Reaper Cannon minigun. They're delivered on the field of battle via drop-pods as soon as an enemy intruder is detected.
Ceph Assault Units, nicknamed Stalkers. They are highly agile soldiers preferring close quarters combat with enemies, using their equipped arm-blades in hit-and run ambush attacks. They can scale walls and perform long jumps, but are less durable than any other Ceph units.
Ceph Combat Command Units, nicknamed Grunt Commanders. Are in charge of leading and directing squads of Grunts into battle. They are armed with high-rate firing pulse rifles, and once a battle begins they activate their shields which emits a red glow covering the whole exoskeleton.
Ceph Assault Command Units, nicknamed Stalker Commanders. Are highly mobile and agile troops acting as field and command units for the Stalkers. Equipped with razor-sharp arm-mounted blades, and energy shields giving them more protection during close quarters combat.
Advanced Ceph Assault Units, nicknamed Guardians. Are highly evolved and advanced special units, with black organic skin covered in a very-high durability exoskeleton armor and state-of-the-art cloaking abilities. They are more intelligent than any other Ceph ground forces and their role in the infantry is to pursue essential targets and defending critical installations from enemy intruders.
The Ceph Tick is a small, insect-like semi-robotic unit that the aliens use to dissolve and transport the remains of the virus-infected humans, in order to minimize the bioweapon's ecological impact. It has a hypodermic needle which it uses to inject dead bodies with enzymes, turning the flesh into a fluid. This is in turn stored in a vesicle on its back, and transported to a collection point.
The Ceph Gunship is a powerful air unit armed with a rapid-fire energy gun, as well as what appears to be a missile battery. It is extremely durable and maneuverable, requiring multiple anti-air rockets to take down, and can eliminate scores of human combatants within seconds.
The Ceph Dropship delivers infantry units on the battlefield via "drop pods". Two types of dropships have been seen so far: the "usual" type, which is seen several types reinforcing alien positions throughout Manhattan, and a rarer, larger version that sports the Gunship's circular propulsion systems. One of these is shot down by CELL helicopters and is revealed to have been carrying not alien soldiers in its pods, but the dissolved remains of virus-infected humans.
Ceph Armored Assault Drones, nicknamed Pingers. Are a type of massive tripod drone armed with powerful energy weapons, EMP emitters and a sonic pulse device that seems capable of severely disabling unprotected humans. They are extremely well-armored, being able to shrug off multiple anti-tank rounds with ease. Their only known weakness appears to be a red section (perhaps a power source or generator) located in the back of their "head".

Crysis 3

In Crysis 3, most of the Ceph are carried over from Crysis 2 in that only a small fractions of their forces are new. Since they are still part of the Ceph Stage 2 invasion, they use mostly the same tactics as their Crysis 2 counterparts.

Ceph Grunt - (Ceph Infantry Unit) They are the backbone of the Ceph armies. Just like in Crysis 2, they use the Pinch Rifle along with energy grenades. Their organic bodies appear to be orange red in color.
Ceph Reaver - (Ceph Assault Unit) They support the Grunts and appear much less frequent. These guys charge the player and always use the secondary/spreadfire mode of the Pinch Rifle along with energy grenades. Their shots resemble the Crysis 2 Grunt Commanders in that the fire rate is slow but very accurate. Unlike Grunt Commanders, they don't have energy shield. They don't apply the hit and run tactic to their targets and their durability are slightly higher than the Grunts. Their organic bodies appear to be purple in color.
Ceph Shadow - (Ceph Long Range Unit) These guys serve as the snipers for the alien army. These guys are only encountered in the last two missions and are fought usually at long range. They carry the Bolt Sniper weapon and do a lot of damage per shot. Their organic bodies appear to be a green blue colored resembling the colour of the Naked Aliens in Crysis.
Ceph Stalker - (Ceph Shock Unit) They prowl the forested/tall grass sections of the Liberty Dome. They are the only Ceph units that can operate without the hivemind / Alpha Ceph. Their exosuits appears to be upgraded from Crysis 2 as they have longer blades and spiked armor. They utilize a technology which blocks the Nanosuit's Nanovision and the Visor so the player cannot track them. As a tradeoff, they can no longer can fire the short range energy blasts as they did in Crysis 2. Mobility wise, they are similar to their Crysis 2 counterparts.
Ceph Spotter - (Ceph Scout Drone) They fly around the battlefields detecting enemy forces. Once they see an enemy, they deploy EMP grenades and call in reinforcements. They do not have any weapons of their own and can be easily taken down or hacked.
Ceph Devastator - (Ceph Mobile Heavy Unit) they act in a heavily armored support role. Just like in Crysis 2, they carry the Reaper Cannon in one arm while the other utilizes the X-PAC. They act more or less the same as they did in Crysis 2 and can be deployed via drop-pods.
Ceph Scorcher - (Ceph Incinerator Drone) These guys have heavy armor that walk on four mechanic legs. They use the Incinerator and can kill enemies very quickly. Once shot at, they transform to armor mode where they can only be hurt by shooting at their sides. They can be hacked which prevents them from transforming into armor mode and as a result, can be easily destroyed. As a last resort against the enemies, they blow up in a large explosion once killed unless shot by an electric arrow which disables their self destruct sequence.
Ceph Sentry - (Ceph Defense Turret) These mobile mechanic units of the Ceph army serve a defensive role. They can be deployed via drop-pods from Dropships at strategic locations. They fire a large amount of plasma energy shots in rapid fire and can be very dangerous is proper cover is not utilized. They can be hacked and behave much like the C.E.L.L. counterpart, the Sentinel. Their turrets turn a 360 degrees angle looking for enemies.
Ceph Pinger - (Ceph Sentry Drone) These large tripod mechanic machines are back and act more or less the same as they did in Crysis 2 and are equipped with the same types of weapons. In mission 4, the player can hack one and use it against the Ceph. They seem slightly weaker than in Crysis 2 requiring less shots from explosive weapons to take it down.
Ceph Gunship (Ceph Air Assault Unit) These air units are armed with a rapid-fire energy gun, as well as what appears to be a missile battery. It is extremely durable and maneuverable, requiring multiple anti-air rockets to take down, and can eliminate scores of human combatants within seconds. They behave much like their Crysis 2 counterparts.
Ceph Dropship (Ceph Troop Carrier) They deliver infantry units on the battlefield via "drop pods". Only the smaller type is seen in Crysis 3 and they are frequently found to deploy Ceph Sentries or Devastators to the battlefield.
Ceph Mastermind - (Ceph Field Commander) These are extremely powerful Ceph units that serve as commanders in the battlefield. They are much higher ranked than the Ceph Commanders from Crysis 2 in that only one is encountered in Crysis 3 at the end of mission 6. The Mastermind serve as a boss and has extremely high amounts of armor and health comparable to a Pinger. Their main form of attack is telekinesis where they use the bodies of dead Ceph infantries as temporary flying weapons that shoot laser and plasma at the player.
Alpha Ceph - This is the leader of the Ceph forces on Earth. According to the intel documents, this Ceph was created after Stage 1 was initialized in Crysis where the nuclear bomb was dropped at the ice sphere. This granted the Ceph enough energy to create the Alpha Ceph. The Alpha Ceph serve as the hivemind of the entire Ceph Stage 2 invasion force and has the power to open a wormhole to the Ceph home planet to bring their Stage 3 warriors to Earth.

Ceph Structures

2ceph — A world map in the last game video clearly showing London and Moscow as the Ceph points of interest.

1ceph — Another world map from from "The Prophet's Journey" Trailer.

Crysis revolved around the discovery of an ancient alien structure in a mountain on one of the Lingshan Islands. Once "awakened", the structured generated a massive energy-draining "ice sphere" which flash-froze a good portion of the island. It also deployed an army of Ceph machines to cleanse the surrounding environs of any remaining human forces. A nuclear attack on the structure simply resulted in the absorption of the blast and the enlargement of the ice sphere. The interior of the structure was devoid of gravity and a large storage and assembly facility full of alien robots; it also contained multiple biological alien beings, which were in the process of emerging from what appeared to be cryo-hibernation. It is unknown what happened to this structure after the events of the game; it is mentioned in Crysis: Legion, however, that one of the involved parties "glassed the entire island", although who this party was is unknown.

In Crysis 2, the Ceph deployed a virus (called "Manhattan Virus", "spore", "God Bug", "Softball virus" or "RapCer" by humans) which resulted in a large-scale infection of many New Yorkers. The virus is generated and released to the atmosphere via large spire-like structures which emerge out of the ground as part of the underground alien structure that Nathan Gould calls the "lithoship". It is revealed that, in addition to the Lingshan and New York structures, the aliens have others built all around the planet, and that all are connected in a sort of network.

At the end of Crysis 2, Prophet revealed a map of Ceph points of interest, which include:

Lingshan Islands, Philippine sea
New York City, United States of America
London, Great Britain
Moscow, Russia
Cairo, Egypt
Hawaii, United States of America
Hong Kong, China
Shanghai, China
Sydney, Australia
Rio de Janeiro, Brazil

Tactic and Strategy

In-Universe

Ceph are more powerful and more sensitive to realized the player appearance than human soldiers, so the more powerful weapons and more strategic tactics are needed.

Game Mechanics

Crysis

Almost all Ceph can be easily defeated with the Gauss Rifle. Smaller ones can be cut down in seconds by the Shotgun, SCAR and the FY71 with the Incendiary Ammo. Larger and more powerful aliens like Scouts and Hunters require LAW, Hurricane and the Gauss rifle to take down.

Crysis 2

In Crysis 2, the Ceph can easily be taken down with some firepower from almost every weapon, such as the SCAR and the Jackal. The more heavily armored and larger variants are more difficult to take down and require heavy weapons, such as the Mk. 60, the detachable HMG, and the JAW, to be taken down. Most Ceph units can also be grabbed and thrown, or killed via the [B] button (Alcatraz lowers his hand and pulls out a combat knife, before setting it to the Ceph's neck on one side. Dragging it to the other side, Alcatraz tightens his grip and blood sprays during the kill. Alcatraz drops the body after it has been killed.), killing them instantly.

Crysis 3

Most Ceph units made their return in Crysis 3, and they can be similarly dealt with as in Crysis 2. The addition of mechanical units - mobile or stationary - can be exploited to your advantage via the Nanosuit's hacking ability - minefields and turrets can make to turn against Ceph units, tougher mechanical units can be temporarily imobilized and reveal their unarmored side vulnerable to attacks(most effective against the Scorcher). Boss units like the Mastermind and Alpha Ceph requires more than just brute force and firepower, tactfully and patiently destroy their various weak-points. Availability of Ceph energy-based weaponry is another plus, as they're rechargeable by Ceph energy cells and if properly exploited, can give you nigh-infinite supply of suit energy and firepower to wither down almost all kinds of the Ceph onslaught (NOTE: Only in the final Mission, Gods and Monsters, can you exploite this. This is by the use of the Ceph Mindcarrier, which actives a state known as "Max Nanosuit", in where Prophet takes no Damage and has unlimited ammo for a short while).

Trivia

Crysis: Legion reveals that the official designation humans have given the species is "Charybdis". "Ceph" is a moniker given to them due to their resemblance to earthly cephalopods.
The cutscene for Only Human shows a planet called "Ceph Homeworld" in the Alpha Quadrant of M33 Galaxy. This is likely a reference to the Star Trek franchise, only the Alpha Quadrant in M33 of Crysis being the Delta Quadrant of the Milky Way Star Trek. Dr. J Keane, head of Xenostudy actually mentions the Ceph Overhives. Meaning worst case scenario, the entire Milky Way galaxy is controlled by the Ceph.
The Stage One Ceph in Crysis and Crysis Warhead in color scheme are similar to the Scrin from the Command and Conquer series, and the sentinels from The Matrix in design. Especially the Scouts.
In Crysis 2 without the helmets the Ceph's faces look like Deadpool's mask.
The feet of Grunts and Pingers in Crysis 2 and Crysis 3 look like the feet of General Grievous from the Star Wars franchise, and Pingers have three legs like the Martian Tripods in War Of The Worlds. This can be overheard when a witness of a Pinger attack is being interviewed by Truth Newton from Radio Free Manhattan on the mission Seat Of Power in Crysis 2 is describing the Pinger as "Something out of those old Star Wars movies. Like War Of The Worlds."
In Zoological taxonomy, Cephalopods are actually a class under the phylum Mollusca which contains exclusively marine invertebrates like squids and octopuses.