The CFE are creatures with two added brain lobes, two updated brain lobes, and several genetic updates. They are capable of remembering creatures, and acting accordingly, as well as having a better survival capability.
The first addition is a lobe that stores the State variable of the 'Friend or Foe' lobe, which is responsible for storing opinions about other creatures, but it is reset by instinct processing (dreaming), the added lobe restores it afterwards. When creatures meet, they instantly like eachother, which resulted in all creatures liking eachother, and norns being beaten to death before they disliked a grendel. This added lobe also makes the creatures meet neutral, so norns are cautious around grendels, and creatures in general will be able to dislike eachother.
The second addition is the elevation lobe. Creatures see other agents by means of the vision lobe, which is the X axis of the location of the agent. This means that creatures are only able to determine how far to the left or right an agent is. This often results in creatures that keep their attention on an agent that is too high for them too reach. The elevation lobe is the Y axis of an object, and with this addition, creatures are able to determine that agents that are out of reach, are not as interesting as agents that are within reach.
The 'Friend or Foe' lobe is the first updated lobe. Two of the four tracts leading from the drive lobe were not in use, which made the impact of interaction next to none. After fixing these tracts, the impact seemed to to be better, but after becoming fertile, the impact became extremely erratic. Because of this, the the tract that handles the frindly and anger impact has been cut in two, and a special rule has been made for the friendly tract.
The combination lobe is the second updated lobe. The combination lobe, and more specifically the drive tracts leading to it, store the learned knowledge of how to reduce drives. When creatures learned something, the previous value was overwritten, which caused the creatures to seem very forgetful. Because the learning is slightly random, some creatures would even refuse to perform a certain action, as it was perceived as a bad action. The tracts now add the learned input to the previously learned input.
These creatures get lonely easier, so that when they are not fertile yet -or with interspecies/same sex, although that requires the updated breeding script as well- the positive interaction has a higher impact.
Now that the memory concerning drives has improved, there was a conflict between twi stimulus genes: 'Heard Creature speak' and 'Swearing lets off steam'. The first increases crowdedness, while the second reduces it. With a group of creatures, this caused a loop where creatures would express, thus reducing their crowdedness, and others would react, raising their crowdedness. This is solved by making the crowded chemical silent in the 'Swearing lets off steam' stimulus, so a creature doesn't realizes it reduces crowdedness.
There was a small presumable typing error in the gene that backs up the hunger for protein when in pain. It converted pain into hunger for protein backup instead, reducing the pain, and eventually raising their hunger for protein.
Creatures would often get stuck at the top of the elevator, and repeatedly push the elevator while starving. This is a conflict between two genes and the wait chemical being issued by the elevator script. They have an instinct which tells them that pushing elevators reduces boredom, while the traveling in elevator stimulus does not reduce boredom at all. The wait chemical caused the creature to remain in the same spot, trying to reduce it's boredom. This is solved by deactivating the conflicting instinct.
The instinct to push button when bored has been reduced, to prevent creatures from becoming button obsessed.
The CFE is unable to get stuck in a lifestage, or go through life without eating. However, the length of their lives can still mutate without the risk of immortals. They are also unable to mutate to unrealistic poses, and most severe limps, but are still able to mutate their gaits, which define the way they walk. The CFEm version can still mutate their genes as regular creatures, but they are compatible with the CFE version.
The original grendel and ettin genomes are based on the expressive versions, which has the breeding problem solved in grendels. The genomes have been updated further in order to make the 'Friend or Foe' lobe work properly. The two genomes didn't have a reaction that gradually reduced friendliness in males, nor did they get aroused by a female; they were always aroused. They also didn't recognize opposite sex pushes as such, and didn't make use of the libido lowerer after mating.
The ettin has a separate version: The DuoCycle ettin. Ettins are often scared, which supresses their sex drive, and with the males not initiating mating, the population quickly dies out. These ettins have sexual cycles in the females, as well as the males, so the reproduction rate is increased.