About the Grim Procession (Orzhov) and Berserker Rage (Gruul) decks:
Wield the spirits, shades, and life-sapping magic in the white and black "Grim Procession" deck to show opponents that their defeat is inevitable. The end is nigh!
Surge to victory with the red and green "Berserker Rage" deck. Summon formidable monsters, and when opponents let their guard down, use might magic to double their size!
A detailed listing of the respective deck compositions is available here.
The new decks can be used in Campaign and Multiplayer play and those wanting to bring these new powers to bear can do so by discarding some currency at the Steam outlet.