User blog comment:FairyRaven/Fairy Tail Chapter 391: Gray vs. Silver, Review and Commentary/@comment-24784846-20140704210129/@comment-25111584-20140705181652

People make mistakes, like when Acnologia was taught Dragon Slaying Magic, but that's irrelevant. Considering Deliora's obsession and easy going attitude outside of that, I'd say somebody cunning like Mard would hardly consider him a threat, and he'd be especially useful as a deterrent against the others who might actually try a coup, as Keith stated. I don't think Deliora would really want to be in a position of leadership, he hardly has anything to be gained from it.