In the Demon Spawn War, the Walking Palm army was a unit of treants serving under a Covenant archangel named Silvanus.
In one of the battles of the Tha'lith Conflict, the Walking Palm battled a demon horde that greatly outnumbered their own. Silvanus asked for treant volunteers to serve as a stockade, meaning that they would root themselves to the ground and then be petrified by spells to turn their trunk, limbs and branches into something as hard as stone. This petrified treant stockade saved the Walking Palm army from being wiped off the map, yet many of these volunteers perished in the process. This was because the battle resulted in much of the stockade being turned to rubble - un-petrifying something that is only half left is death to most creatures, including plant-life like treants. A few months after this battle, Asmodeus ordered a bastion built here to protect the petrified wood. The fortifications of Leza-Sîk are built among these petrified timbers.