Can this card be used when resolving the Before Combat phase for Dragonlord Eregax? Horodrax states "Activate this card to receive a +2 bonus to Resist test". Eregax says "Before Combat: Test Resist (17). If you fail, you may not activate cards this combat". Is Horodrax considered a Before Combat ability? If so, I don't think Horodrax can be used because the rules require that the adventure's before combat ability be resolved "even before any of your own Before Combat special abilities". Man, I've been playing this game too much! Think I'm reading too much into this. Would still appreciate an answer. Thanks.
You're allowed to activate one card in the Before Combat stage, whether that's in the enemy's segment or your own. I don't see why Horodrax would be any different in that regard from any other card. So sure, you can use Horodrax to get a +2 to that Resist check, and that counts as your single allowable activated card for the Before Combat phase.