Board Thread:Questions and Answers/@comment-15732371-20140715093532/@comment-1038387-20140715101111

He was killed by a Radion bullet, the only material that can kill a New God (well, other New Gods can kill New Gods, but non-New Gods can only kill them like this).

I'm not sure why he and the others weren't resurrected, but I guess it has to do with the Source in life and death. The Black Lanterns were connected to Nekron, who probably has no control over the Source.