Board Thread:Warhammer 40k General Discussion/@comment-25618639-20150118044502/@comment-24944355-20150125015426

Yes but Deliverance lost was set during the heresy & the Emperor was sitting the throne to hold the demons back while his forces eliminated them from the webway after which he could reinforce the webways walls. From that point the webway would cease to be an immediate concern & the Emperor would no longer be needed to hold the demons out.