It has been 39 years after the First Advent, and the Synthesia organization has managed to advance Cuneate Line technology to its present state. This new approach gives a much more controlled environment for implant users to acclimate to their new hardware, evading potential catastrophic incidents from recurring.
To become a full-fledged Afferent, implant users have to achieve "stable reality" during their first dive into neural space.
During this first dive, the trainee will be plunged into "unstable realities".
They will need to harness their mental fortitude to navigate these unstable realities till they arrive at the present stable reality. If unsuccessful, these unstable realities will overwhelm their consciousness, erasing them from the world.
Successful trainees then gain the title of "Afferent" and are welcomed into Synthesia, where they undergo further training to specialize in a class of reality manipulation. It is to note that the first dive is also known as "potentiation", and this is a permanent event.
Once trainees cross over into the ranks of Synthesia as Afferents, they will never lose their reality warp abilities, but at the same time, have to be forever burdened with maintaining stable reality for their individual self, and not letting unstable reality (aka 'chaos') takeover.
This is also the origin of the commonly said catch phrase "potentiation is permanent".
In Synthesia, Afferents are split into 3 divisions, based on their specialized niche. These are the Combat Squadron, Scout Squadron and Support Squadron.
Within each squadron, there is further specialization. For example, in the Combat Squadron, Afferents who wield reality warp energy in cybernetic weapons are called blade meisters, while Afferents who directly warp energetic spacetime are called battle mages. There are also Afferents who absorb realities into their body frame as a form of powerup, and they are known as berserkers.
While the number of Afferents fighting the war against the Sentients have increased dramatically over the years due to Synthesia's innovation and technological advancements, the majority of humanity still have no control over reality. Many are unwilling to undergo potentiation due to the inherent risks involved.
The humans who help Synthesia in support roles are known as Symbiotes, and they perform a wide range of jobs, from administrative help to engineering duties. Likewise, the Sentients also have the help of their own Symbiotes, mainly the ones who were corrupted during the First Advent.