 Both the title of the episode and the invocation spoken by the character of Sammael refer to four of the nine choirs of angels in Christian mythology . Christian <unk> holds that there are three groupings of three choirs each . The Thrones are the third @-@ highest ranking choir , belonging to the group charged with attending to God , and are described as stern incarnations of holy justice . Dominions , the fourth @-@ highest choir , belong to the group appointed to deal with God 's creations . Dominions lead the lower orders and impart wisdom to humanity . Powers belong to the same tier as Dominions , and are tasked with countering the threat of temptation by the devil and demons . Principalities are the seventh @-@ highest ranking choir and belong to the lowest grouping of angels , those most likely to appear to mankind . Principalities oversee those humans who rule over others , teaching kings and heads of families the skills needed to lead . 
