Tzaran Streams

These are Magical streams that pervade real space and allow travel between Archipelagoes. Haunted by unbound spirits and what can only be described as demons, they are both the backbone of inter-Rift trade and communication, and a danger to all who travel unprepared. They provide infinite energy if one knows how to harness it, and millions of possibilities. They have never been fully mapped, and they continue to extend out beyond anyone's furthest imagination. Some experts have guessed that of the existing Streams, only 0.01% are known about if there even is a limit. The Streams have entrance and exit points which act as the only safe way for any vessel to use them as transport, otherwise, you'll be ripped apart quark by quark. The streams also have tides that move along them, seemingly at random. The tides speed up movement that goes with them and slows down ship movement against it.

To travel in the streams, an Inkallu trained in Navigational capabilities is required, as they can guide the vessel through the Streams. An alternative is using an onboard computer to navigate from Waypoint to Waypoint, though this limits the area a ship without a Navigator can travel to any place linked to by a Waypoint beacon and the surrounding areas that a skilled non-Inkallu pilot can guide the ship to.

Meta-wise, imagine it as a mix of the Warp from Warhammer 40K and Hyperspace from Star Wars Legends.

Manifestation

The Streams look like a giant multicolored wormhole when manifested in real-space, and when inside the wormhole, they look like large tunnels made up of the same colored "stuff".

The Streams interactions with realspace are complicated. On occasion, one can find tears in the streams where you can dip in and out in between entrances, but mostly the streams only appear in realspace as large multicolored wormholes. 
The same techn9logy that anchors tracking beacons in Stream space is what allows the construction of large bases and stations anchored within the wormholes, and what allows blockades in Stream Space to occur, though due to the tenuous nature of getting too close to the edge of the Stream tunnel, it is never possible to enact a full blockade. When construction such stations, it is bets to use a disposable workforce, as anyone who spends time in Stream Space is liable to go mad.

Alternate Names

Laran knows them as bloodveins, as a mythologized story of the life of the Lati Mul-Zamain credited him as having created the wormhole space with his own blood.
Achroni knows them as the Prime Gift, given by their diety the Nameless.
The name Tzaran itself is used by the scientists who study the Streams, named after the corruptive effect that the Streams have on naked flesh.

Ecology

The Ecology of the Streams is a complicated topic but it can be summed up as relying entirely on large predators. The large Predators keep the smaller creatures that feed off the arcane energies of the streams. There is no plant life, and few can claim to have seen the hunters and hunters, with no reliable descriptions, but all sensitive to Inkallu energies can feel the creatures nearby. Ghosts have been known to harness the largest of the creatures to attack ships, hoping to enact vengeance or wreak havoc.

Type

Natural

Sentient Activity

Many try to harness the energies created by the Streams to varying success. Trade relies entirely on it and explorers who map new streams gain great wealth and fame. Mining companies tend to fall flat on their faces as there are no known minerals or formations, though anyone who can harness the near-unlimited energy provided by the Streams has grown fabulously wealthy. Siphon Gear to gather and refine the Depthsuede is immensely volatile and hard to make, leaving governments or megacorporations as the only ones equipped for Siphoning.

Miscellaneous Notes

New Streams are constantly being mapped, and the myth of the Core continues to motivate explorers.
The Streams themselves are mapped like rivers, with branching pathways, smaller streams that break off or rejoin the main ways, a constantly shifting environment that makes travel hazardous without Navigation Stones, and dead ends that can leave one trapped in the streams for eternity.
The physical description of the Streams is that of giant tunnels that ships travel through. Gravity seems to not exist within the streams, as records show that if someone jumps off, they simply float through space until they are pulled back in, get eaten, or crash against a wall and disintegrate if they haven't already died of hunger, thirst, or lack of Kali Energy. Staring out at the Streams for too long is said to make most go mad, though those already lacking a firm grasp on reality seem to be made saner by the streams. Some scientists theorize that it forces viewers to reach a certain equilibrium in their sanity, not quite mad but not quite sane. It is still crazier than most would accept in even the most savage societies.