Also known as 'embodiment or re-embodiment, (re)jacketing, resleeving, and reshelling
The first artificial bodies available for use by virtual entities were known as remotes or surrogates, teleoperated robots which could be operated at a distance by a human or AI. Later, remotes were used by uploaded humans (virtuals) to interact with the physical world. Another option which became available at this time was downloading an entire infomorph into a physical body. At first these bodies were sophisticated robots, direct descendants of the teleoperated remotes available previously. Because many of the first robot bodies used by downloaded mentalities were available via rental or hire-purchase arrangements, these became known as rental bodies.
During the First Federation era, with the development of engeneration technology, it became possible to install the upload into a biological body. In the early days of this technology the upload would be installed into a body created from the upload's original DNA. As the technology became more sophisticated it became possible to choose from a range of different bodies, with different physical characteristics, different augmentations, different sexes (including herm, merm and neut) and even different species.
Many colonists have been downloaded into radically tweaked bodies capable of surviving in environments very different to Earth-Normal (see the article on Pantropy for more details). Eventually, after the discovery of Xenosophont species on distant worlds, it became possible to download into alien bodies and interact with these civilisations directly (see article on First Contact for more details).
In the modern era many sophonts of all types deliberately upload themselves so they can download into a new body (or several) of their own choice. The range of bodies available for downloading is very wide, and includes robotic, biological and hybrid/cyborg options often with advanced capabilities. Common names for such new bodies include 'shells', 'jackets', or 'sleeves'. Some sophonts hop from shell to shell at will, following current modes and trends of fashion.
Downloading Simulations (Simms) and Digital Sophonts (Digis)
As well as uploaded biont mentalities there are many different types of infomorph who have never possessed a physical body. Simms (recreations of fictional or historical persons), Evocations (close approximations of real bionts created using data obtained from their exoself), digis (artificially generated virtual beings inhabiting virtual reality scenarios), and aioid infomorphs (copies or partial copies of sentient AI programs of many kinds) all could take advantage of downloading technology to become installed in a physical incarnation of one sort or another.
Many choose to be installed into robot bodies; aioids quite often choose entirely non-biont vec bodies, such as bushbots or starhands. But simms, evocations and digis often choose forms that closely resemble their virtual form. A virtual entity based on a biont form may chose a robot body that replicates their own species; these synthetic bodies are often robust and serviceable while still reproducing the biont experience closely.
Other virtuals choose to be incarnated into a body made of flesh and blood. Of all the classes of virtual being, only uploads (and a few simms) have samples of their original DNA from which a new body may be wrought. All other virtual beings have (virtual) bodies which are essentially fictional, and this means that before downloading can begin a suitable body must be genetically designed from scratch to replicate that virtual form as close as possible. Designer algorithms developed many millennia ago by Genen vatbrains allow this process to be achieved quite successfully in most cases.
Some fictional sophonts are quite a challenge to provide bodies for; many stylised cartoon virtual entities require neogen bodies which bear little resemblance to any other living creature. Incarnated virtual halflings, kinder, goblins and dragons are reasonably widespread, and often find company among other mythological and fictional races on world-reservations such as Ribblehead and Mysterland. Competitions between incarnated fictional virtual species are quite commonplace, and range from friendly contests to bloody warfare (usually resulting in reincarnation for some, or all of the combatants).
In some cases a virtual sophont (or several such entities) decide to create an entirely novel real-life body for their incarnate; the result (known as a reling) can be very imaginative and unique, defying any classification among existing clades. The most exotic of these creations can be classified as true relmonsters, living creatures that may cause havoc in a real-life environment.
In other instances the virtual sophonts require physically sophisticated bodies, because their virtual personas are physically or mentally superior to nearbaseline humans and other species. One early example was the incarnated Fifth Men; a race of virtual humans created to populate a partial simulation of a classic Old Earth novel by Olaf Stapledon, these creatures were engenerated in the Bolobo system, but genetic neuro-engineering was not sophisticated enough at that time to faithfully reproduce the advanced minds of those speculative creatures, and the experiment failed. Later attempts to incarnate the Fifth Men, and other even more advanced and specialised simms and digis from later fictional narratives were more successful.
The Supervillain Problem
In many fictional VR narratives, role-playing games, and worldbuilding scenarios, there are a number of virch beings who are specifically designed to be antagonists, and are sometimes preconfigured to be entirely evil. This preconfiguration often consists of the construction of a psychopathic or otherwise morally or perceptually limited individual. However this individual may be remarkably intelligent, especially the end-of-level antagonists found in certain adventure games. In most jurisdictions these limited, some might say blighted individuals are prevented by law from ever becoming incarnate; but in some free zones and elsewhere the incarnation of such antagonistic creations is condoned, even welcomed as entertainment. Sometimes hordes of mildly warped lesser beings such as trolls or imps are incarnated to be their minions.
In some cases the incarnation of an antagonistic virch is followed by periods of conflict and bloodshed; the incarnated villain may not realise that e has been given physical life as part of an extreme form of entertainment. On occasion the antagonist will win control of a system, and either rule despotically or attempt to invade nearby stars (with disastrous results, one way or another.) But in many cases the incarnated supervillain, once given a new physical and biological persona, starts to change psychologically until e is closer to the mental norm for the species of his physical body. This process usually results in the reformation of the antagonist's character, and eventually eir rehabilitation. Institutes for the Benefit of the Formerly Evil exist in many major systems, designed to assist such supervillains and their minions to become useful members of society.
Reincarnation - Text by M. Alan Kazlev Religious conception that there is a soul or personality that continues after the death of the physical body, and is reborn and lives again in a future life. An important component in many religions, also a common folk-belief. See also rebirths.
Relbox - Text by Jorge Ditchkenberg A robotic or nanodevice for relifing. Relboxes tend to be tightly controlled (but, regrettably, not tightly enough) by archai, angelnets or guardians, to avoid creating dangerous relnano, monstrous reltrapworlds and relmonsters.
Reltrapworld - Text by Jorge Ditchkenberg A fraction of virtual worlds are run by bizarre, breakaway virtual beings, which often have only a limited understanding of the rl. For the real persons entering or interacting with them via virtual reality, they appear as nothing less than nightmares brought to life, or deadly traps. Reltrapworlds are illegal and punished by erasing the virtual existence(s) who created them. Nevertheless, some still sneak through.
Relworld - Text by Jorge Ditchkenberg  A symbolic term for all relifed things, sophonts, places etc. Place in real life controlled by virtuals. First applications were advanced, semiautomatic rl/Net interfaces with limited manipulation by virtuals. They soon grew and diversified, including learning centers, entertainment places and relfactories. Includes dangerous reltrapworlds.
Virtual Body - Text by M. Alan Kazlev One's av (avatar), the body one takes when 'facing in virtual reality. By means of the virtual body, even the sensorium of the ordinary body is transformed to appear and feel different than it does in rl.