"There's no turning back now. The plan has entered its final stages..."
A Dark Agenda was Teppen's eighth expansion and added the game's final post-launch hero, the mysterious woman from the game's character stories, Ada Wong. The card set details Ada Wong's "mission" to gather her 15 fellow characters and guide them towards the Land of Illusion, as well as her encounter with the last member of the Striders, the Special A-Class Strider Hiryu.
Series and characters included as Unit Cards in this expansion (Bold indicates a series new to Teppen)
- Darkstalkers: Morrigan Aensland, Lilith Aensland
- Devil May Cry: Dante, Nero, Nico, Eva, Vergil
- Mega Man X: X, Zero, Colonel, Iris
- Monster Hunter: Rathalos, Nergigante, Felyne, Lagiacrus, Grimalkyne, Zorah Magdaros, Namielle, Astalos, Rajang
- Ōkami: Amaterasu
- Resident Evil: Jill Valentine, Albert Wesker, Ada Wong, Carlos Oliveira, Tyrell Patrick, Robert Kendo, Nathaniel Bard, Annette Birkin, Drain Deimos, Oswell E. Spencer, Ivan, Nemesis, Brad Vickers, Chris Redfield, Hunter Gamma, Sergei Vladimir
- Sengoku Basara: Oichi, Azai Nagamasa, Kyogoku Maria
- Street Fighter: Ryu, Chun-Li, Akuma, Sakura Kasugano, Abel, Oro, Ken Masters, Sagat, Gen, M. Bison
- Strider: Hiryu, Solo
''A Dark Agenda" contains examples of:
- Another Side, Another Story: Many of the Action Cards give an insight into Ada's mindset and her thoughts while she was acting as the mysterious woman.
- Fun with Acronyms: "A Dark Agenda" neatly abbreviates into A.D.A. or Ada, the focus of the expansion.
- The Reveal: This expansion revealed that the “Mysterious Woman” who had been manipulating the 15 other characters on the roster was Ada Wong, but who she was working for would remain a mystery until Breath of Resistance.
