"To patron Clavicus Vile, beacon oer our affairs, we owe our successes and social stature. Our bond with Vile makes us unique among our kind, for his guidance steels our savage craving with reason and savvy. For him we live amidst mankind, and twist them to our will from offices of power."
Look, its fine if in your downtime you want to point at a chicken and say thats not a chicken because a chicken doesnt look like that, but if you insist on doing that on a forum I read, tetchyness happens.
The text clearly indicates a pact with the Prince of plots.
Fair enough, though I'm not sure how the chicken comment is related. The text does indicate that Vile and the vampires made a deal. If that's the case, I won't begrudge it or won't say it doesn't make sense, because it does. However, given all the other things I see indicating that the deals with Clavicus Vile usually don't work out for the people who made them
Spoiler His "cures" for both vampirism and lycanthropy, his solution to the end of the Civil War in Skyrim, one of his solutions for getting rid of Barbas etc.
makes me consider the possibility that the bond between them was not created by the vampires seeking Vile's help, but rather Vile coming to them with what they now celebrate as good news. If this is the drawback of a deal between Vile and a mortal, it fits in with his usual MO. I also wonder why the Order would strike a deal with Vile when they could have asked Molag Bal, their original patron.