'Crisis on Infinite Earths': Oliver Queen's return from Purgatory is going to be complicated but not impossible
'Crisis on Infinite Earths' Part 1 broke the hearts of many a fan by killing off Oliver Queen / Green Arrow (Stephen Amell) in a not-so-well-received last stand.
As of Part 3, Oliver's soul has been empowered to become the Spectre, which would normally mean we'd get to see him resurrected soon, except that the episode's ending complicates things a little bit. The entire multiverse has now been destroyed and all life except for the seven Paragons has been wiped from existence, including Oliver's soulless body.
With Oliver's body destroyed, his soul doesn't have anywhere to go. Although one could argue that his soul isn't any normal soul anymore seeing as it's basically been hijacked by a celestial version of the Punisher. The Spectre is an ancient mystical being, largely believed to be one of the first angels created by the Judeo-Christian God and the living personification of divine wrath. His power is nearly limitless and the Spectre's only real weakness, and a minor one at that is that he needs to be tethered to a human host in order to manifest on Earth.
However, we don't know if the Spectre would be able to survive the anti-matter wave, especially since the last time we saw Oliver's soul, he was still in Purgatory. While the Spectre should be able to teleport himself out of limbo, we didn't actually see Oliver transforming into the Spectre yet so as far as we know, he was still there when the wave hit Earth-1 and obliterated the universe.
Of course, it's possible that Purgatory isn't tethered to any one universe since we see a version of Jim Corrigan (Stephen Lobo) who's from a different Earth. This suggests that Purgatory might actually exist outside normal space and time, so it should theoretically be able to survive the death of the multiverse.
Ultimately though, we just know Oliver's coming back. He's the Green Arrow. If he's going to die, it won't be offscreen and his importance to the story in itself gives him an instant Get-Out-Of-Purgatory-Free card.
'Crisis on Infinite Earths' Part 4 will air on The CW on January 14.