Hierarchy among Devils.

Cain stood over the corpses of the fallen devils with a pondering expression. 

'It works.' 

The magic signals the devils sent out upon death could still be considered spells or skills. {Seal} is a spell capable of cutting off the flow of mana for low-level spells and skills completely. Hence, Cain was able to stop the devils from sending the magic death signals out.

Cain looked down at the new devils of which he had never seen before, the {Sentinel Drones} he had personally laid to waste. They looked even more unique than the other devils he had seen previously. They had dark shadowy eyes with red centers covering their entire body structure as well as thin tendrils of fleshy material dangling from underneath them. 

'From the looks of it, they served as the sentries of the devils. The only question here is, what exactly do these devils need sentries for?'