Anyone connecting to the Grid, whether remotely or immersed, is represented by an avatar or “shadow.” Even operators of grid-deaf systems are represented by shadows when they are encountered by gridrunners accessing their systems physically.

Every user must have a shadow to interact with any portion of the Grid. A shadow takes the form of a three-dimensional interactive model that cannot overlap with any other object in the Grid—that is, it occupies its own virtual space. More than just a reflection of its user’s personality, a shadow is a collection of allocated memory that can transfer the user’s personal programs from site to site.

Shadows also represent their users in shadow combat, and any attacks made against an avatar actually represent attacks on the hardware and software of the user’s computer.

Shadows can take many forms and have many functions, and many are quite sophisticated, but even an amateur Grid user can put together a unique shadow within a matter of moments. All grid-capable computer hardware comes with a selection of default avatars that can be used on the fly, but the typical Grid user creates her own custom shadow.

If a shadow is destroyed, the user must create another one from scratch, re-designing its appearance, re-installing software, etc. This can take from a few minutes to hours or even days.

Every avatar is linked to a particular user and system. A floating, formless shadow that drifts from domain to domain and cannot be touched might prove quite useful to some-one with subterfuge on her mind, but no such shadows can exist, rumors and legends not-withstanding. This restriction is built into all of the software and hardware that makes the Grid work.

No “typical” shadow exists—a user may represent himself with anything from a stick figure to a Roman gladiator to a Ray Harryhausen skeleton. Lovable cartoon characters are quite popular, as are heroic figures such as wizards and valkyries. Most Grid users prefer to design their own custom avatars as unique personal statements. Others (particularly wealthy users with plenty of money to spend) pay professional avatar designers hefty sums of money to create shadow that cannot be duplicated—the virtual equivalent of hiring a personal tailor or fashion designer to forge a unique “look.” A massive tool-set is available for the creation of avatars, so Grid users have almost boundless resources available for creating avatar designs.

Avatar size is generally limited to the Grid equivalent of a Medium-size character, since collision problems could occur with giant shadows in small node spaces. Most Grid domains have programs that detect and dispel inappropriately sized shadows, although talented hackers can sometimes modify their avatars’ sizes for short periods of time before their handiwork is detected and scrapped. Otherwise, the Grid imposes few limitations on avatar appearances, and the virtual community tends to encourage creativity. The scope and quality of the shadow’s customization sets the amount of time (from a free action to days) and Computer Use DC (from 2 to 45) to perform it. There is no penalty for failing a roll other than having to start again.

Note that changing a shadow’s appearance can prevent an observer from recognizing it, but has no effect on traces or spikes and so on. Trying to disguise one shadow to look like another requires the same time as it would have taken to design it and a Computer Use check equal to the original DC +5.

Besides representing its operator on the Grid, a shadow also has the ability to store software. Whenever a user installs a program, she must store it in her avatar’s available active memory or it cannot be used on the Grid. Avatars can typically hold up to ten blocks of available memory, regardless of the specific VR software and hardware in use. Some special abilities and gadgets can improve this number.

If the avatar doesn’t have enough available memory blocks to run the desired program, the user must delete other programs to create enough space for the new one. Each program has a standard memory cost, which indicates the number of memory blocks required to run it. The program author chooses an object to represent the program on the Grid during the design process, and the shadow wears, holds, or carries that object from node to node as long as it has the program in its memory.