aka the "Pattern of Death".
The name for the blood fueled pattern located somewhere in Arden, underneath a great tree. Originally unpowered, Jericho powered it partially with his blood. Loen then supplied more blood, and Jericho then finished powering it.
It is dark in color with scary death dark motifs.
The Tree above it has a passage down a long set of stairs that leads to it. Random has placed guards at the entrance to this passage. Silas has installed a series of lethal traps on the staircase that the guards know how to disarm.
Lowen has now walked it and gained the ability of the Dark Pattern.
This allows him to walk in shadow similar to the Pattern, except that everywhere he goes it is almost always night. (he can force the issue to go somewhere there is daylight but by default it always uses night).
The activation of this pattern seems tied to an effect in which shadow extended into the Void Sea slowly.
Dworkin later performed a ritual which fully activated it. When this happened the advance of shadow was much swifter, but it eventually stopped.
People known to have walked the Dark Pattern: