The DEAD shall RISE

Death:

In the hidden bunker, Batman escapes and confronts Darkseid. He states that he will make an exception to his "no firearms" rule and shoots Darkseid using the bullet that killed Orion. As Darkseid gets shot he fires the Omega Sanction from his eyes, and hits Batman, before the Omega Sanction hits Batman he silently says "Gotcha".

Superman having just returned from the 31st Century, where he was given access to the ultimate weapon, the Miracle Machine, a reality-altering device created by Brainiac 5 of the Legion of Super-Heroes. Upon seeing what has become of the earth, Superman goes into a rage as begins to use large blasts of his Heat Vision to decimate Darkseids forces en masse. He makes his way to the hidden bunker and attacks Darkseid, finding the charred corpse of Batman within.

Life After Death:

It is later reveled unbeknownst to anyone that the Omega Sanction does not really kill its victims, it instead sends their consciousness through time and space to alternate realities and times. Bruce Wayne's mind still lives in the far distant past, where he is hanging out with cavemen.

It is unclear if Wayne's mind will be able to return to the present but his body was destroyed. Thus it is unclear how Wayne will be able to recover from his current disconnected state even if he is successful in returning to the present.

Mortal Remains:

Whatever it means, the body left behind was recovered by Superman. He returned the cowl to Nightwing and Robin, to be left in a memorial similar to the one Batman made for Jason. At Alfred's insistence, no public funeral was held for Batman, and Robin, refusing to believe he was dead, prevented them from declaring Bruce Wayne dead, leaving his friends and family without a chance to properly honor him. Wayne's body was buried in an unmarked grave next to Thomas and Martha Wayne.

Some weeks later, as Gotham City was going through a rampant crime wave following Batman's disappearance, Green Lantern Hal Jordan and Barry Allen, the second Flash, who had returned during the Final Crisis, met each other at Wayne's grave for a private farewell to their friend. Although Hal was somber given the loss, coupled with the earlier losses of Arthur Curry and J'onn J'onzz, Barry reminded Hal that they, Superman, and Green Arrow all died and returned, and if anyone could beat the Reaper, it was the Dark Knight. Unfortunately, soon after they left, the criminal Black Hand, under the influence of mysterious force, dug Wayne's skull out of the ground, and used a black ring to begin the reanimation of Batman as a member of the Black Lantern Corps.

He did come back as a Black Lantern, and is was F@$# awesome, but on the third page of the comic Nekron said "Connection Severed" and it was good-bye Bats. Shit...