The Adversary's goal is to destroy this universe and replace it with a new one under his control. He is an energy being with no physical form and so magic must be used to defeat him, but he has also shown weakness to cold iron, steel, and Adamantium. The Cheyenne Indians were aware of Adversary's existence and their shaman, Naze, often battled him. Naze eventually trained Forge to take his place. Adversary felt that his biggest threats on Earth were Storm and Forge, so he took on the form of Naze and tricked Storm into thinking that Forge was trying to destroy the Earth because he was under the control of Adversary. He had opened a portal to his dimension through which many demons were pouring out. Adversary led Storm to believe that this was Forge's doing and sent her to stop him. Forge was near the portal because he was trying to close it but Storm saw him and stabbed him and they both fell into the portal. Roma, the Goddess guardian of known dimensions had been captured by Adversary and the X-Men were battling him. Storm and Forge escaped and came back to help in the battle. The X-Men sacrificed themselves so that Forge could cast a spell converting them to energy which he could use to defeat Adversary. Adversary was defeated and sealed away in another dimension and the sacrifice of the X-Men would keep him there forever. Roma stated that the chaos that Adversary believed in had the potential to better this universe and so he must not remain sealed away. She then resurrected the X-men.
Major Story Arcs
Adversary can be seen as one of the demons at The Infinite Embassy, more precisely he was at the Devil's Advocacy, inside the Embassy, arguing with the other demons who should be the true Satan.
He can assume any form he desires. May be fought successfully through magic, but not through most forms of physical force. He is vulnerable to iron, steel and adamantium.