Apologies in advance if this topic has already been covered, but I could find nothing in detail about it. Did anyone that played the PTR find out what this new mystery tied to the new respec system is? It's not just the Den of Evil deal is it?
No, it is not just the Den of Evil. Andy/Durial, Meph, Diablo, and Baal each drop their own separate essence. Put all four of the said essences in the cube and you will have yourself what is called a "Token of Absolution." That will respec your stats/skills.
"New Mystery" for 1.13