What ability happens first? Because that would change a whole lot.

My take...

For Rudor, "After defending" I'd take it to mean after the two steps that relate specifically to defense in the Attack sequence, specifically Roll Defense Dice and Modify Defense Dice. After that, there's no specific defense related activity. I'd put Rudor's ability to trigger before the Compare Results & Deal Damage

Tactician, however, is clearer. It states "After you preform an attack" and that I would take to be after all the steps of the Attack process being from Declare Target through Deal Damage, then Tac triggers.

Both abilities trigger after the attack. This means you resolve them in initiative order.