I'm creating a breton paladin build an I'm wondering if he would side with the blades and kill paarthurnax or side with paarthurnax. If I have to I guess I could kill him but I don't like too. I just don't know which one seems morally right for my playstyle as you could really make an argument to support both sides.
He would kill him without a doubt. Paladins aren't all different from the Blades. Would a True Paladin let a necromancer live because it's his friend or relative? I doubt it.. being a paladin is a serious job. Look what happened when Aribeth de Tylmarande started having doubts.