In Rain's universe, Virtual Intelligence (VI) robots are ubiquitous, performing virtually all of the physical labor in Second Life society.

The term Artificial Intelligence (AI) fell out of favor with the development of the Beltrami AI Proofs. These proofs showed true strong AI to be physically impossible to create, causing the term to become obsolete from a PR standpoint. Research into what used to be called "Weak AI" continued and was rebranded as "Software Intelligence" or "SI".

True sentience can only exist in beings with a soul. This immaterial aura can be observed with tools like the PKE meter, but actual understanding remains limited.

A VI is effectively an artificially programmed synthetic brain, similar in many ways to the synthetic neural structure that Second Lifer brains use. Absent a soul, they are not and cannot become sentient. They can, given enough experience, training, and proper management protocol, give the appearance of sentience.

VIs have their own unique attributes that set them apart from SIs.

While a SI can have it's software copied from a saved image in seconds, a VI mind is individually grown. Modern production methods allow the average VI training manager to train up a new batch of VI brains in under a year, batch size depending on the experience of the training manager. The finished brain has what one might consider a high school level of education. From here, the brains are usually sold and their training continued by the new owner.

Just like Second Lifers, VIs cannot be "hacked" like a typical computer or SI can be. You can lie to them or trick them, but there's no way to load malicious code onto them. Computerized subsystems can be hacked, but proper design and compartmentalization limit what can actually be done. The best one can hope for is to gain access to their internal PDA and the data it contains. In theory, a VIs management data stream can be hijacked and routed to a third party. This would allow the third-party to gradually manage the VI into being loyal to them and not the owner. In practice, authentication and management documentation quickly expose such methods before any meaningful damage can be done.

VI brains become more valuable the longer they are in use and the more experience they gain. Proper tracking of VIs in commercial and industrial settings is incredibly important, as VIs in identical bodies may have brains of vastly different age, experience, and capability.

VIs used as personal servants receive extra attention to management from their owners. Extended management time plus the experience that comes with directly tending to their owner results in VI servants effectively becoming extensions of their owners will. In many star systems, ones personal servant VIs are considered protected property in bankruptcy cases and cannot be seized by creditors.

Since both VIs and Second Lifers have robotic bodies, there are steps taken to visually differentiate the two. The most obvious is the lack of a face on VIs, a featureless visor covering the optics. They posses minimal body styling, basic male and female styling is common. Colors are typically bland, any customization is usually limited to what makes them identifiable to their owner. ID numbers are standard on the exteriors of VIs. It is highly illegal in virtually every system for a VI to claim to be a Second Lifer out in public.

Rain and Anton share a common pool of VI servants that they both manage together. Mismatched ear tips are the visual feature that identifies them as their property.

This fantastic ref sheet was drawn by the talented ThiccRobots over on Twitter. They do great work.