The Launch Exclusive Content for "BlazBlue Entropy Effect" includes three Avatar skins, two HD wallpapers, and a special Phenomena Art Book.

Q: Where I can find the DLC contents(Special Phenomena Art Book and wallpapers)?
A: After you get the DLC on the Steam, select Blazblue Entropy Effect in your Steam Library, right-click and select Manage. Then choose Browse Local Files to access all DLC contents located under the "BlazblueEntropyEffect\Launch Exclusive Content" folder.