What have we seen in the books that would have stirred the White Council to action toward the Knight of the Blackened Denarius? The Denarians generally seem to plan and execute their own individual agendas, with some occasionally grouping together (Like Nic, Deirdre, Tessa, etc). The one time we saw them go after humanity in any sort of direct way (Nic's Shroud plague), a WC wizard stopped them before it could get started. No need for official WC intervention there. When the Denarians went after The Archive, a WC Warden took action to recover the Accords Signatory (Ivy). Again, no direct WC action required.
The WC does not get all worked up over matters of fair play, free will, championing the little guy, etc. Their laws are just there to be enforced upon themselves and any plain-vanilla mortals who dabble in the magical arts. If the WC attempted to get involved in the Denarians using human Hosts, they'd have to go on the warpath against all Accords groups who prey on humans in any way (BC and WC for food, Denarians for Hosts, etc). If they attempt to dispute a Denarian Host's use of magic (like Thorned Namshiel), the Fallen in the Coin could rightly say "my use and knowledge of magic predates your species' existence, so you have no jurisdiction over me or my Host".
So unless the Denarians take direct action against the White Council, I really don't see these two bodies coming into direct conflict.