For all of enchantment fans' bluster about Theros block's insufficient mechanical connection to the card type, the fact is this setting has done a lot with and for enchantments. Enchantment creatures in particular are a major feature of Theros, and of course the most prominent of those are the Gods - indestructible and hence very difficult to deal with. As a balancing feature, there are a number of pieces of removal that were developed specifically to combat the Therosian pantheon, and LoadingReadyRun has just previewed the ultimate solution to a God problem in a video.
Exile target enchantment. If the exiled card is a God card, search its controller's graveyard, hand, and library for any number of cards with the same name as that card and exile them, then that player shuffles his or her library.
"It is done." - Elspeth
This is definitely a flavor home run - possibly one of the most epic-themed cards in all of Magic and really a great use of the name (which means, of course, "godkilling" in Latin). The art and flavor text convey the presumptive ending of the block story - Elspeth runs Xenagos through with Godsend - in a perfect way.
It's almost a pity that such a design is necessarily a sideboard-appropriate card. In Block Constructed it'll find its way into maindecks because of the prevalence of the Gods, especially in multiples, but in Standard and Modern that is less so. Still, it's an extremely potent weapon when in fact used against a God that was intended as a finisher or that the whole deck was built around, and two-mana enchantment exiling isn't exactly bad on its own. All in all, this is a definite Spike-Vorthos appeal card - a pushed piece of power rare removal with kickass flavor.
One note: The existence of this card doesn't mean Xenagos is in fact dead - since no Therosian God has ever been killed in the storyline before, particularly not one who also has a mortal, planeswalker body, it's possible that Elspeth will only be able to remove his godhood, and he will escape by planeswalking.
What do you think of Elspeth's final act of defiance? Let me know in the comments.