Board Thread:Warhammer 40k General Discussion/@comment-67.197.44.118-20130216115719/@comment-1657156-20130414005958

Marshall Silverman wrote:What you say is true, if The Emperor dies, then that breach would be opened and all sorts of demons and creatures will come forth. When and if that happenes i am very confident that the Adeptus Custodes will hold them off, atleast for a long while, until some way to close that breach is found, Ahhh... But, remember.

The daemons behind the breach have been bottlenecked there for 10,000years. The daemons that invaded after Magnus caused the breach to widen significantly had only been gathering since the Emperor had begun the Webway Project (which wasn't very long).

Ergo, the protectors of the Imperial Palace were able to repel the daemons.

But now there's 10,000 years of daemons that have gathered at the breach; and because the breach was enlarged, it's likely gathered more powerful daemons as well.

Thus, were the Emperor to perish, and were the breach to burst open completely...

it would be an extremely cosmic explosion.