The death of Koroe got noticed by other, weaker commanders up above.
Of course, the movement of the tree barrier arose some suspicious feelings, but never in their mind they thought that someone could actually find and kill the necromancer! Because he was necromancer that could refine bodies, his skills to disguise were close to the perfection.
And as someone who wields the death aura like true black magic, such thing as being found out truly hadn't flashed even once in the minds of the other commanders.
Their ranks were 95 and 91, so if Koroe died, then their death is also inevitable.
"Should we run away?"
"There is a possibility of the killer being left without any energy, but... It's not worth risking... There is not such thing as 'pointless death' in our Divine Death Coffin Alliance."