So let's get to these mechanics.
Fateful Hour is an ability that will activate while your life is at 5 or less. Not only that, but it will stay active as long as those requirements are met. But keep in mind that if you gain life for some reason, and it goes to 6 or above, Fateful Hour abilities will vanish. So it's interesting to see how this new ability will affect comebacks in games once this set is out.
And the next ability is Undying:
Creatures with the undying ability will "come back to life" as long as that creature has no +1/+1 counters on it. And when it does revive, give it a +1/+1 counter. Perhaps we will see some counter shenanigans to keep abusing this mechanic. Either way, I'm sure that creatures with Undying will be quite interesting. These creatures will be quite fun to use against cards with Infect, especially since they will keep losing that counter from undying.
More from Dark Ascension to come. That's all for now.