The secret behind the deaths and resurrections of superheroes in the DC Comics Universe was once revealed by Green Lantern. As a hero that's been to the other side, Hal Jordan let readers in on what it takes for a hero to be able to come back from death.
The death of a superhero was once a shocking thing. Some of the earliest deaths in comics were such big news, the entire world took notice. Whether it was Robin's murder in Death in the Family or Superman succumbing to his injuries in The Death of Superman, such departures once shook fans seeing their favorite heroes removed from the board. However, as high-profile deaths became more of a common sight in comic books, so did seeing characters eventually come back. Currently, it's not unusual for a superhero to experience a death and then simply return in a matter of years, or perhaps even sooner.
Few comic events have had more commentary on the death of superheroes than the 2009-10 story Blackest Night by Geoff Johns and Ivan Reis. The event sees the DC Universe invaded by a swarm of Black Lantern rings, resurrecting heroes and villains alike as zombies under the control of Lord of the Unliving, Nekron. As a number of heroes who have come back from death charge at Nekron in Blackest Night #5, the villain reveals that he is the one who prevented them from permanent deaths and made it so they could to return to life. He even forcefully inducts heroes such as Wonder Woman and Superman into his Black Lantern Corps to prove their lives belong to him. However, in Blackest Night #8 Green Lantern Hal Jordan refutes the villain, saying that even if Nekron opened the door, he was "the one who walked through" and that the same is true for every hero who came back from death.
The idea that a hero must want to come back is actually hinted at earlier in the event when the Black Lantern rings attempt to resurrect the former Dove, Don Hall. However, Don is noted as being "at peace" and can not be reanimated. The revelation puts the deaths that superheroes experience in a whole new light. Those who come back do so because they have a desire, while some stay dead because they're content being off the mortal coil.
While fans may get irritated at the overzealous deaths and subsequent resurrections of heroes, the fact that there's a logic for why they come back at least makes sense. More often than not, heroes like Superman or the Flash are killed in their prime, when there's still so much more they can do. If presented an opportunity to come back, it's no doubt that some of the heroes most committed to justice would turn down eternal peace to fight the good fight alongside their comrades once again. The insight provided by Green Lantern is a good explanation for why fans should never count their favorite DC Comics heroes out for good in the highly likely chance of their death.