If the 616 and the Ultimate U are gone.And Battlworld is formed using the Fregments of Universes to make Battlworld.
Some Characters made it using the life raft and most didn't.So whatever doom did is not explaned yet So Battlworld is like Dooms verson of the MU like House of M in a way.So the Ultimate End book out Wednesday is like a patchwork of Dooms verson and the Characters are the same.How did they die and then end up there