File:Aegis.png

Summary
AEGIS (Aperture Employee Guardian and Intrusion System) is the main antagonist of the Portal 2 Mod, Portal Stories: Mel. He can speak and make autonomous decisions, but they are based on protecting the scientists and does not show any self-awareness or sentience. He can only follow protocols and what will be safest for the scientists. He also seems to have great power over the facility, like GLaDOS, such as dispensing turrets, starting a flooding sequence or a asphyxiation program and even control testing tracks. He is first encountered in old Aperture when you have almost escaped the Lima Whiskey testing track as its radars can probably pick Mel up and immediately deems you as a threat, assuming you killed all the scientists in the Bring Your Daughter To Work Day incident.