Marvels of demon engineering, these four structures are off the coasts of Torvild Isle. Built of bones, stone, and flotsam, in the Demon Spawn War (8972 GE, they kept the Sôvuk Sea Gate open. For 19 years, they kept a rift open between Bal-Kriav and the demon world Kurun'Ush. The were called Manes Chimneys because manes, the lowest demon stage, were the fuel. This turned Torvild into a hot-spot, with Covenant aquatic armies battling the demon legions coming out of the rift.
The aquatic demons came from a foul and noxious wetland. Leaving their Abyssal home behind, they passed through to Bal-Kriav. They swam a dark watery tunnel where the weaker demons were picked off by those stronger. It wasn't a test, just the demon's nature. Eventually, higher-ups decided to police and patrol it, corralling the mobs into an army.
- from the artwork - "Sôvuk Gate"
The writings in the artwork Sôvuk Gate are true when they speak of a channel beneath the island. This channel is 100' below the waters on on Torvild's west side. At 20' in diameter, it is many miles long. At its end is an ancient chamber where a rift between worlds once spiraled in the darkness.
For nineteen years (8978 GE - 8997 GE), the Manes Chimneys were anchors to another world, devices the weave spiders were incapable of closing. Each of these towers, said to have once stored the energy of a hundred thousand manes, were costly build and fuel. The demon lord Gorag'theg staking all on his invasion of Bal-Kriav. Too well defended, the Covenant never succeeded in taking any of the Manes Chimney. For lack of fuel, with no more manes to power them, the Sôvuk Sea Gate eventually closed on its own.
When Torvild was overtaken in the Dark Revolt, some began to wonder if the Sôvuk Sea Gate was truly closed. The Manes Chimneys were cleared and reoccupied, becoming trade stations between the living and the island's three undead holds.