The most basic of elemental beings, fundamentals are creatures on the very border of living or animate. At the very bottom of Inner Planar ecology, their exact nature has eluded scholars and travelers alike since their first recorded discovery.
Fundamentals were first recorded only a scant two centuries ago, described in very hyperbolic terms by Revorus, a Mystaran adventurer and self-proclaimed scholar of the elemental planes. His original reports described them as bat-winged beings of pure elemental essence: both the most dangerous of all elementals, and the purest form of elemental there could be; it is from this original description, accuracy in other aspects aside, from which the name "fundamental" first arose. These reports were quickly examined by the scholarly community, which was sent in an uproar by the apparent discovery of such a major yet never-recorded caste of elemental. One of the few not caught up in the academic fervor was Zamik Feron of the Doomguard, the leading skeptic to Revorus's claims (in large part due to Revorus's status as a Prime). After years of study, Feron concluded that Revorus's reports were entirely baseless and that no such creature existed; itself an overstep that he suffered some embarassment for in the years to follow.
As was finally concluded, the fundamental was a being that for centuries before had never been recognized as a living form of elemental. Review of the literature revealed past observations of fundamentals dating back centuries, always either misidentified as scraps of element animated by some unknown force, or not even recognized as independently animate at all. In fact, even today a debate rages on the matter of if fundamentals are heavily animated portions of an elemental plane or living beings with only the smallest fragment of that necessary to grant life. All that can be said on the matter is many even outside the community of Inner Planar scholars are curious on the matter, seeing fundamentals as closer than any other being to that tenuous border between the animate and the living. (This is to ignore the brief popular theory of a century ago that fundamentals were some strange larval form of elemental, quickly dismissed by most sages due to the fact that the existence of such a stage of life fit into no theories of elemental life cycle, and further that all elementals interviewed on the subject denied such a stage existed. Still, the theory still exists amongst some of the more outre, fringe greybeards.)
With no intelligence to speak of, fundamentals are on the level of insects or other vermin at best, and possibly not even any more living than a plant. They have no apparent society to speak of, nor even any awareness of the existence of others of their kind as more than mere elemental.
Fundamentals do not seem to feed on any substance or secrete any sort of waste, a fact often used as evidence for those on the side of "animate elemental matter". However, they do appear to interact with their environment in a manner far more curious and playfully than most mere animates, occasionally swarming outsiders much in the manner of a cloud of fireflies though making no effort to harm. Nothing is known about the lifespan or life cycle of a fundamental, or even if they have anything of the sort, as fundamentals seem to do quite poorly when removed from their home plane; most disintegrate within hours of removal for reasons unknown, but theorized to be related to a lack of exposure to the massive quantities of their personal element and the contrasting sudden exposure (as part of the objects that surround them) of their opposing element.
The beings themselves, if in terms of the food chain of the Inner Planes if nothing else, seem to fulfill the role of plant life or plankton. Many animal-esque beings native to the Inner Planes, and some intelligent beings, feed upon fundamentals in lieu of inanimate element, apparently finding them a more efficient or simply preferable food source in comparison. It would seem that they concentrate elemental energy within themselves much in the way the above comparison creatures concentrate ambient energy of their environments, allowing it to be processed in a more efficient manner.
Appearing as nearly two-dimensional ribbons of elemental substance or form, fundamentals have been described by many (including Revorus in his original reports) as bat-winged beings. This is a somewhat inaccurate description, likely compounded by their tendency to flap or undulate as they glide through their element. Their edges do tend to be somewhat ragged, however, almost as if they were ripped from the surface of their element like wallpaper from a wall. Fundamentals vary in size from a few inches to upwards of two feet across, though they rarely stretch out their full length. When still, fundamentals are almost indistinguishable from their element.
- Planescape MCIII, pp.46-47