The Episode 34: Justice League Dark Add-on for DC Universe Online has 3 achievements.
In the JLD: Shattered Gotham Raid (Normal), reach 50% Madness during the Tala fight and remain above 50% Madness for the rest of the instance.
During the JLD: Fellowship of Arcane Light (Event, Normal or Elite) Raid, locate the books: Ebontome (Abridged), Magic for Dum-Dums, Adventures of Alley-Kat-Abra, "Sleight of Hand : dnaH fo thgielS" by Giovanni Zatara, Seances: Beyond the Veil, A History of the Starheart, Cei-U and Other Magic Words, Sargon the Sorcerer's Autobiography, and To Eternity and Beyond.
During the JLD: Darkness Rising (Event or Normal) Alert, defeat 151 werewolves in the European Castle.