User blog comment:Jopjopjop/Volume 20 Spoilers/@comment-3290441-20150823171930/@comment-124.195.116.184-20150826215237

Samael is still in Hades's hand, AFAIC he is not in a good relation (understatement) with DxD. Plus, 666 is not really a dragon, so why would they need Samael for??. Shiva is the back up plan prepared by Azazel in case 666 awakens and that is more than enough.