“Mortuos Antiquos” eh… maybe, take your pick I guess, the germanic peasants and lords are the ones naming everything, and the saxon/celt/roman undead seem unlikely to provide answers as to their origin.
Based off that; “Alten-Toten” seems a bit more likely to me and has a ring to it, but I’m an ignorant Englishman and either one of those titles might sound totally lame to someone who knows the language lol.
True and true. ;P
Though I am personally fine with the faction name the “Ancient Dead”, what do you think of the “Altvorderen”(= ancestors)(Though I think it sounds better with its proper German noun marker: “die Altvorderen”) or “Vordern”(short form; probably the best suggestion, since it is catchy, german, but doesn’t really sound or look that way and it works with a “the”) or “die Verewigten”(= the deceased/eternalized/immortalized) or “die entseelte Legion”(and there you’d also have Latin) or simply “die Entseelten”(= the deceased, ~the ones, which souls have been taken away)?