That actually gave me a few ideas on it, IF it ever gets done, which is unlikely, namely it would actually run more or less smoothly, since Ares would know Lucas's reasons (as she is partly in his domain) and would sorta explain things without the need for much "clenched teeth politeness" on Lucas's part. Adding to it would be the fact that Ares would point out he also took care of those that fought against the very tyranny Lucas hates. It'd begin with polite distrust on Lucas's part (and I would make a point of highlighting said distrust is HER problem, not HIS), but it'd quickly get sorted out (as, well, gods aren't morons and this one would take the quick time to explain it).
Mind you, I'm just thinking a big IF here, it's unlikely to ever happen, but it's good to have a contingency plan for once. ;)