The rune formation they were facing now went by many names across the continents. Ken's personal favorite was the name 'Death Loop'.
Divided in two segments, the death loop was a formation that required two massive runic structures to be constructed in opposing directions. Facing each other, these runic constructions took control of the area in between, and gave birth to an inverse plane. The actual battlefield formed a loop with the inverse plane, hence the name.
Those who died in the battlefield ended up in the inverse plane, and then through the loop, they could return to the battlefield as ghosts, riding on specific mediums, which in this case, had to be the 'dust' accompanying the horde. These ghosts could take over any dead body, or sometimes even possess the living combatants in the battlefield, and continue to fight like a revived soldier, regardless of the extent of injuries on their new or old body.