Assimilation

Assimilation is the process by which the Borg add new members and new technology to the Collective.

The Borg assimilate beings from every species they consider worthy (with the exception of some species on whom assimilation attempts fail, such as Species 8472).

Once a species, or starship, was found worthy of assimilation the Borg would assess its tactical strengths and weaknesses and adapt if necessary.

When the Borg arrived to assimilate a planet they would come en masse. The El-Aurian Guinan compared a Borg attack with a storm of Jaradan Aser beetles after they destroyed her homeworld.
 * This strategy in assimilation is not universally exclusive. In all direct Borg attacks on Alpha Quadrant species (specifically the Federation, on Earth), a single ship has been dispatched, rather than several at once.

When a starship faced assimilation they would be hailed by the Borg and, depending on the type of Borg vessel, they might have a chance to withstand them. If not, the crew of the ship would spend the rest of their lives as drones. (VOY: "Dark Frontier")

The Borg used several hails to inform future drones of their fate:
 * We are the Borg, you will be assimilated. Resistance is futile. (VOY: "Dark Frontier", "Scorpion, Part I")
 * You will be assimilated. Resistance is futile. (ENT: "Regeneration")
 * We are the Borg. Lower your shields and surrender your ships. We will add your biological and technological distinctiveness to our own. Your culture will adapt to service us. Resistance is futile. (Star Trek: First Contact)

In potential drones the process begins with an injection of nanoprobes into the bloodstream of the victim via assimilation tubules or the installation of implants in an assimilation chamber. The microscopic devices rapidly spread throughout the body, assimilating the victim's cells and hijacking their internal mechanisms. Once a sufficient level of assimilation has been achieved, the nanoprobes begin replicating larger implants, some of which erupt through the skin. The nanoprobes attach themselves to individual cells, altering them on a submicroscopic level. The parent nanoprobes focus primarily on cells involved in the production of red blood cells, and the red blood cells themselves. The bone marrow is quickly infiltrated and the victim's own DNA is used to bring more and more nanoprobes to "life", quickly altering and in many cases assuming some or all of the functions of that cell. Within two minutes of the initial nanoprobe injection, there are 15 to 25 billion nanoprobes working throughout the victim's body.

Nanoprobe concentration in the key areas of neurological function is extremely high, especially in the key structures of the brain's limbic system. This is no doubt responsible for the sedated state the subject enters within seconds of nanoprobe primary infiltration. In fact, the color of the victim's skin turns a pale gray and the blood vessels immediately under the epidermal layer turn a darker gray as billions of nanoprobes take their place along side the Borg modified blood cells.

At this time the hive's newest drone is usually escorted to an assimilation pod by two other drones, where additional physiological and surgical alterations are made. The victim is scanned by a variety of sensors for a quick determination of the drone's most effective role within the collective. Borg devices, synthetic glands, neural processors and other modifications are now made on the drone to build him/her into their hive-assigned role. For most humanoids, one of the limbs is removed and replaced with an armature, while one of the eyes is replaced with an ocular implant. The body is fitted with exo-plating attached directly to skin or bone. A neural transceiver is implanted into the upper spinal column (or other similar nerve cluster), linking the individual's mind with the rest of the Collective through subspace. From this time on, the drone is connected directly to the Borg's subspace communications network, and the drone literally hears the collective voices of others in the hive. Recovered Borg have stated that the effect is almost hypnotic, and quite overwhelming. Once that is accomplished, the Collective begins to re-structure the person's neural pathways. At this time the host's individuality is lost.

When the assimilation process is complete, the once-humanoid lifeform is now completely supported by the installed Borg technology of the drone. There is no longer any need for nutrition; this is simply eliminated by the direct power conversion process that takes place in the Borg alcove. The newly-implanted cybernetic technologies of the drone give it the ability to withstand environments that would destroy most organic lifeforms, from the the wide variation in planetary conditions encountered in the galaxy to the vacuum of space.

As expected, such a denatured humanoid becomes completely dependent on the collective consciousness and the neural link that keeps the drones connected to each other and the hive mind. If a healthy drone's link with the collective is cut, within a matter of hours the original immune system begins to reactivate and a rejection syndrome develops as the body attempts to repel the Borg artificial implants. While this in itself often proves fatal, some Borg have managed to successfully break away from the collective and return to something akin to their former self. Some implants remain in any recovered Borg, for some reason not being attacked by the body's defensive measures.

The Borg also assimilate environments and technologies, making them capable of refitting an entire starship within a matter of hours after assimilation of the crew. The Borg have assimilated technologies that allow some areas of their technology to regenerate with extreme speed, making it very difficult for defenders to remove the Borg component structures and modifications in order to regain control of their vessel. Examples of these anti-resistance technologies include autonomous regeneration sequencers.

In The Expanded Universe

 * Elizabeth Singh, after surviving the Borg attack on the USS Rebellious (NCC-1807) at the Battle of Wolf 359, witnessed her twin children, Esthappen and Rahel, being assimilated by the Borg.