Rifts of Time

The rifts of time are the product of the destruction of timelines. They are places where many ruined dimensions mingle and merge in a haphazard and chaotic fashion. The rifts are highly dangerous and deadly, and the disjointed nature of time and space within them means that few if any that venture into them ever return. Navigation becomes nearly impossible within them, since the shifting state of the realm removes the traces of your travel, and destination and origin can become indeterminable. Nonetheless, there are forms of life that have become capable of surviving in this inhospitable domain.

These extremophiles often take a variety of alien forms and shapes. Some resemble demons, or fungal growths, while others are shapeshifters or still more bizarre forms. Tokigakure nin call these beings "Kaiju" as a generality, since they are usually hostile to normal life-forms.

Creation
The rifts have always existed, and always will. They are the primordial chaos that predated the natural world, and will resume or take its place upon its destruction. The rifts "consume" dimensions or timelines that have become unstable, subsuming the space-time of the doomed world into itself. Menma Uzumaki has destroyed many timelines and dimensions by sundering key points of stability within their history. In this way, the rifts have actually expanded into many timelines or dimensions where they would not have otherwise existed, further undermining the integrity of the multiverse.