Another interesting thing that came to mind while associating the Utautai Sisters with the 7 Deadly Sins…was that, there cannot be dark without light and vice versa. If the sisters represent a dark element, then they must also reflect a bit of light as well.

Check out this site to read more on various types of VIRTUES.
http://www.deadlysins.com/virtues.html

The most interesting to me was this:

The Contrary Virtues were derived from the Psychomachia (“Battle for the Soul”), an epic poem written by Prudentius (c. 410). Practicing these virtues is alledged to protect one against temptation toward the Seven Deadly Sins: humility against pride, kindness against envy, abstinence against gluttony, chastity against lust, patience against anger, liberality against greed, and diligence against sloth.

Even if one of the sisters represents one of the Deadly Sins, they will also represent a Virtue that will cancel out one of the other’s Sin, like Four’s chastity against Five’s lust. Very interesting.

The more I think about it, the more I think DUALITY and DICHOTOMY will play a large role in DOD3.