The crux of Theros block's plot revolves around a mortal - Xenagos, the Reveler, the ambitious Satyr planeswalker, becoming divine, and threatening to bring down an entire pantheon. Heliod conscripts Elspeth to stop him, and Ajani joins her - and eventually she's successful in saving the plane via an act of Deicide. However, it's not actually made clear whether the death of Xenagos-the-God means the death of Xenagos-the-mortal. Here are the possibilities for what happens to the most charismatic villain of recent Magic history:
- He's gone for good. The card text of Deicide makes it clear in no uncertain terms that whatever God is targeted isn't coming back, and if you subscribe to the interpretation that Xenagos was wholly turned into Nyx-essence by the Great Revel, then there's nothing left of him after he takes Godsend to the heart.
- His divinity is gone, but he lives to plot another day. Xenagos getting away as a weakened but still living planeswalker means Elspeth has won an important victory, and finally managed to hold onto a plane she now can call home, but also sets up another recurring villainous planeswalker. It seems the Creative team has learned its lesson about killing popular planeswalkers after one appearance thanks to the ongoing grief over Venser's death. Xenagos would make an interesting addition to Magic's own Rogues' Gallery, having distinctly different motivations than the calculating Nicol Bolas and the frankly unfathomably inhuman Phyrexians and Eldrazi.
- He's humbled and reforms. To end the story of Theros on a truly upbeat note, something that's few and far between in Magic storylines (even the return of Avacyn to Innistrad had bittersweet elements for Garruk, to name one), perhaps the titanic battle with Elspeth might convince the jaded Xenagos - who truly believes the other Gods are horrible tyrants - of the misguidedness of his mission, and he'll start planeswalking in the name of liberation.
All in all, we'll get an answer by the time the third part of Jenna Helland's block novel Godsend is released.