"There are very few of us now who saw first-hand what the Envoys could do."
Envoys are an ambiguous class of "super soldiers" (alternatively, they were freedom fighters to some, terrorists to others) who were created alongside the technology of the Human Race hundreds of years ago.
Envoys were highly proficient at adapting to the most advanced of technology, such as being trained with the use of the Cortical Stack and the consequential ability to needlecast to off-world destinations, often without the experience of Sleeve Sickness. They were exemplary fighters whose abilities are renowned but now mostly faded to legend.
They were led by Quellcrist Falconer, who claimed to had been the creator of the stack technology. Disillusioned by her own invention, she gathered followers who turned against the United Nations Interstellar Protectorate.
There is no specific timeline of events, but eventually Takeshi and his sister, Reileen, were captured by them and eventually joined them. That time, Falconer planned to sabotage the universal stack technology by the means of the Rawling Virus. However, shortly before her attack, Rei, who worried about her and her brother's safety, decided to sell them out. Nearly all the Envoys have been killed, with the siblings being the only known remaining Envoys. They were hunted and killed by the United Nations' military forces for allegedly rebelling against the government of the day, which ruled over all known human settlements.
The modern perception of the Envoys is that they are an extinct terrorist group who sought to undermine the power of the United Nations and were rightly killed off. This perception meets the official narrative that children are taught in schools with Envoys being treated wholly as 'bad guys' who were rightly killed for their crimes. This false narrative is discovered by Kovacs when he stumbles upon an exhibition that glorifies the brutal execution of the Envoys by CTAC at an exhibit being visited by a group of school children at the same time as him.
Trained and conditioned with the philosophies of Falconer, the Envoys could employ powerful abilities others don't have. There is some ambiguity as to the nature of their 'spatial awareness' ability -for want of a better term.
- Lack of Sleeve-sickness - Envoys do not experience sleeve-sickness, which makes them perfect for short notice combat in off-world settlements as they can needlecast into a new sleeve and be ready for combat immediately.
- 'Spatial awareness'/Super hearing - Kovacs demonstrates his ability to hear or detect enemies that are otherwise unseen in both Episode 1 and Episode 9. The process looks similar to echo location or sonar, and it allows for an Envoy to precisely locate an enemy and engage in combat more effectively.
- Construct manipulation - When trapped inside a Virtual Reality construct, for example for interrogation, a kind of meditation can enable them to consciously manipulate and escape the construct.
- Heightened intuition - It is thanks to this legendary Envoy ability that Bancroft decided to resleeve Kovacs and employ him as a detective. At many points, Kovacs has displayed an uncanny deductive ability, able to realize people's motivations with little data. For example, only by noticing Tanaka's expensive bouquet of flowers to Kristin Ortega, Kovacs deduced his guilt and therefore his possible role in a cover-up.
- Foresight/Anticipation - In Episode 2, Kovacs anticipates/foresees Mr Elliot kicking the table and attacking him (while he's still strapped to a wooden chair), which allows him to react quickly.