Archimedes the Old may have been slain during the final phases of the invasion. While I can neither confirm nor deny this, after Julius Dryden had fled to Cove in fear, Archimedes took up his shepherds crook and joined those few attempting to rescue Magincia from certain doom. There were several points where I observed the old mans lifebar drained dangerously low before he managed to recover, and he had finally disappeared the last morning.
Some claim that he sacrificed himself to weaken the ethereal portal, while others claim that he went in search of his old nemesis, Julius Dryden. Still, others claim that he has been kidnapped. Nicholas the Old has mentioned knowing something of his whereabouts, but has remained tight-lipped on the subject.