The magical image of the decan per Crowley’s 777: A man, dark, yet delicious of countenance
Ruler of Libra is Venus. Ruler of this decan of Libra is Saturn, which is exalted in Venus. Ruler of the Threes is also Saturn, through Binah.
36 Airs of the Zodiac gives the deity as Kairos, a god associated with the right or critical time; time in general being a function of Saturn. This god was said to have a front forelock of hair, but no hair on the back of it’s head, the implication being that the right moment had to be seized or it would be too late to grasp it. Often the knowing of this moment involves pain and knowledge (Saturn) of the heart (Venus) – as well as formal contracts bindings (Saturn) connecting people (Venus).
Just for fun, first here are the depictions of this card from RWS, Thoth, and Tabula Mundi:
And here is the “man, dark, yet delicious of countenance“.