From the publisher's website:
Adepts of the Arcane presents twelve new antagonists for players and gamemasters to use in their M&M System roleplaying game. These include Armageddon Girl, The Aspirant, Carmody The Rebel, Cold Comfort, Deadworks, The Magister, Midnight Edition, Nether, The Prime-Mortal, Radian, Sweet Synn, and Troll. In addition to the new antagonists, Adepts of the Arcane also presents numerous origins, adventure hooks, and supporting characters in a series of innovative sidebars throughout the book.