Is it required to tell the opponent which marker the Servant is connected to? I could not find anything in the rules that requires you to, please cite if I missed anything. Thank you!
Since the controller isn't explicitly private in and of itself and the peripheral doesn't have anything making its identity private information, then it will be open information which camouflage marker is controlling it. Now, I think that peripherals simply by their nature forces you to disclose it regardless, but I have a harder time finding that to show it.
