One of the major features of the Theros block Hero's Path events has been the hero cards, meant to be used against the Challenge Decks at the Game Day for each set. Theros got an impressive seven of them to choose from; Born of the Gods will have the same, and five of them were revealed on MTGSalvation today by Rumor Mill user SkyShield21:
Exile The General: Creatures you control get +1/+1 until end of turn. Untap them.
You may play an additional land on each of your turns.
Exile The Savant: Tap all creatures your opponents control. Those creatures don't untap during their controllers' next untap steps.
Exile The Tyrant: Creatures your opponents control get -1/-1 until end of turn.
Your starting hand size is increased by 1.
Your maximum hand size is increased by 1.
Of these, The General, The Savant, and The Tyrant are apparently from prerelease packs, The Explorer is the Launch Weekend puzzle reward, and The Vanquisher is the Game Day hero. The fact that The Savant taps down opposing armies implies that the Horde of Minotaurs will in fact attack and block like ordinary Magic creatures, though exactly how the Challenge Deck will work this time around remains to be seen.
It seems as though all of the color-associated prerelease heroes will have "Exile this:" effects, much stronger than the tap abilities of the Theros heroes but only usable once per game. The red-associated one might be targeted direct damage; and the green could be artifact or enchantment destruction, assuming the Challenge Deck contains any, or else creature token production.