A web rupture is a weak area in the Web of Magic that looks like a hole into darkness with glowing and pulsating blue-white webbing stretching off into infinity. Depending on the level of degradation, and if not repaired, it will turn into a rift. Most of these web ruptures are found by weave spiders and patched up.
In the Dawn Era, there were thousands of web ruptures. Most of these were a product of making worlds and seeding them with life, the work of the Creationists, while others were intentionally made with null mines. These devices were used to pierce the Web of Magic, creating rift to other systems. In the Demon Spawn War, demons used null mines to create web ruptures and then more mines to turn them into rifts between the Abyss and the mortal realm.
Flapping like a tattered sail in the wind, a rupture in the Web of Magic can be an easy way to cross-over to another world, but also a quick death from the fangs of a weave spider.
- excerpt from the tome Izrukîn Sa Thir - "Rift Beginnings"