The Demonic Invasion Arc was an Arc of Blue Exorcist and considered a series continuation of where it left off shortly after the defeat of Satan, after Satan enters into one of his hibernation cycles after his defeat at the hands of his two eldest Hybrid children it became apparent that his Regent would take care of his throne in Gehenna, little did he know that his Regent Son Azazel was planning a new invasion into Assiah and had been orchestrating this plan for 17 years but Azazel soon finds himself surprised with the existence of an older Hybrid son of Satan that can actually harm him.