From the official website:
We’ve just refreshed our free-to-play Hero rotation with a fresh set of seven Heroes who stand ready to start smashing towers at a moment’s notice!
As always, fresh accounts begin with five free Hero slots, and the two remaining slots can be unlocked by reaching player levels 12 and 15, respectively.
Here are your free heroes for this week:
Raynor
Diablo
Tyrande
Zeratul
Muradin
Gazlowe (Available after you reach player level 12)
Tassadar (Available after you reach player level 15)
