Hello, everyone! This is my first post on BoLS, so I'm very sorry if this topic has been discusses before.
Today while facing against my friend's Dark Angel's army a problem came up. Some of his units have Preferred Enemy (chaos space marines), and I understand that to mean any unit coming from Codex Chaos Space Marines. I was using Khorne Daemonkin and had Chaos Space Marines in the list as well as a daemon prince. We agreed that the rule applied to the marines, but weren't totally sure about the daemon prince as he appears in both Codex Chaos Daemons and Codex Chaos Space Marines.
Does anyone have any source for clarification on this? Does the favored enemy only apply to armies using Codex Chaos Space Marines, or does it apply to Daemonkin as well? And if so, would it only work on units the Daemonkin share with Chaos Space Marines (so not the daemons)?