In Tintibulus, the third layer of Acheron, all is empty. The air here is only just above freezing, the light is never brighter than dim twilight, and the only sound is the ever-present hum by which the layer gets its name. Not merely the lifelessness of Thuldanin, here even the remnants of war are gone. No monuments, no devices, no ruins. Even the iron of Acheron has long since given way to stone scoured clean. Tintibulus is the layer of absence, of the fate of war after even memorials have crumbled away. Not even rust monsters make their way this far; the only beings one is likely to ever encounter here, besides the occasional visiting mortal, are the xong-yong called to the layer by its natural tone.
The "cubes" of Tintibulus — here a gray stone with the texture of volcanic rock — are much more fragile than those of higher layers, and their collisions much more vibrant. Here, the six-sided shapes of Avalas and Thuldanin no longer survive. Instead, each "cube" takes on the form of another polyhedron, more sides shown the smaller they become. The first collisions in this plane ages ago of the true cubes that once were found here left octahedra, the remnants shattering into frozen dust. Further collisions brought these octahedra smaller and smaller before they gave way to new shapes; first deltohedra, then dodecahedra, and finally icosahedra as the smallest of the "cubes" of Tintibulus. And of course, each collision in Tintibulus brings a resounding tone that adds to the eternal reverberation of the layer, an endless tolling for the past death of all.
Though the plane has no natives, its lifeless nature, general safety, and relative solitude lead many to use it as a center for experimentations; many powerful and well-known arcanists and alchemists, both planar and Prime, have set up laboratories in Tintibulus in order to test their most dangerous products without risk to anything more than massive chunks of stone. It is this nature that brings the plane's only divine realm, if only in part: a portion of the realm of Wee Jas extends up from Ocanthus, to allow the arcane power of her and her followers to be tested in new, unimagined ways. Additionally, modrons are known to have mining colonies on this layer (in addition to Ocanthus), though what they could possibly be mining for on Tintibulus none can say, and they've certainly never revealed it themselves.
- Dragon #350 - Core Beliefs: Wee Jas, pg.20
- Manual of the Planes (3e), pg.126
- On Hallowed Ground, pg.167
- Planes of Law - Acheron, pgs.11,23