Terror And Fear.

The three demon kings attacking this plane stood at the very back of their army as they watched the ongoing fight. Their Heralds used to stand around them but they have been sent to lead the demon army into battle. They are needed to fight the grand gods. 

Aeternus is one of the three demon kings. His avatar is a tall dark red armored monster. He has claws the size of knives on all four of his giant arms. His dark red skin is not smooth at all. It is lined with sharp tiny spike-like thorns. There are other spikes that extend from his elbow and knees that reach lengths of a meter. These spikes can be used as improvised spears.