In his book Rhetorius goes on to say that
the ruler of a decan affects a planet positioned in that decan that it rules.
Then he goes on to give the description of each decans.

Here is the problem.
Is it only me who noticed that 1. his descriptions of each decans
do not correspond with the general meaning of the ruler of that decan
and 2. his descriptions of each decans correspond with the decan in
opposition quite perfectly.

For example, he describes the first decan of Aries as, to paraphrase
danger, plot, and fluctuation and the first decan of libra means danger
in young age, but later find property.

Also the first decan of capricorn means public bussiness, griev over
children, experience danger when young, but good when old.
The first decan of cancer means public business, griev over children,
bad in young age but good in old age.

If you compare the meaning of decans
the first 18 decans starting from Aries correspond
with the 18 decans starting from Libra.

Through out my study, these meanings are not related to
triplicity, domicile rulership, exaltation or sect.

He gives independent meaning of decans of the planetary
rulers of these decans.

I speculate that these meaning have something to do
with municipices and liturgi, which are ministers that rules
each decans. However, the surviving information on these
are so incomplete and scarce, I could not make
the connection with confidence.

If you want to know what I mean, read Rhetorius the Egyptian please.