It actually IS about the blood, because a Numenorean lived far longer than, say, a Dunelending or some other 'lesser' human. At the End of the Third Age, though, Numenoreans in Gondor had mixed with other human races. Only few men, among them the rangers of the north (including Aragorn), still were true Numenoreans (the rangers were descendants of Arnor, where Numenorean had always been strong). The royal line of Dol Amroth actually had some elven blood, but they were an exception. There even was a civil war in Gondor once, when one of the Kings was not fully Numenorean.it's not about the blood, before Numenoreans arrived at Elenna(the island) they all had human blood, only one had elven blood in him(the king=Elros brother of Elrond)
That was all the kingdom of ARNOR. You must not confuse them with Gondor, they were seperate kingdoms from the beginning. They had the same founders, but all three of them died rather quickly Gondor (who arrived too late in the war against Angmar) really had not much relationship with the elves apart from fighting alongside them in the Last Alliance. That alliance, however, was initiated by the King of Arnor, Elendil.So I suppose it was just me imagining things then, when I read about the Númenóreans fighting against Sauron all through the Second Age, culminating in the Last Alliance at the start of the Third? I guess it was me imagining things, when I was reading about the wars in Arnor, with Lindon siding with Arthedain and Cardolan against Angmar?
They were on good terms, yes, but not enough to design their armors in a similiar way - after all, they're on opposite ends of the map. Gondor fought mainly against the wainriders and other tribes of Rhûn during the Third Age.