The teaser came and went as soon as it was shown. As the die hard analysts had figured out, the brand new hero will be Magni Bronzebeard. He will be an alternate hero for the Warrior class and will have only aesthetic changes, including a quick hammering animation when the Warrior’s hero power Armor Up! is used. The blog post has mentioned “heroes” constantly which would mean the assumption that the other classes will eventually get something similar to Magni and have different hero portraits you can change to. If they follow suit with Magni, they will have custom animations, specialized emotes and voices and unique card backs.
Magni Bronzebeard and all future custom heroes will be available for the Mac, PC and iOS versions of Hearthstone for $9.99 USD. There is no solid release date for this yet but it’ll most likely be sooner rather than later.