: Swords were made of bone?
It wasn't competely unknown. The oracle of Delphi, for instance, once told a man that, one day, his horse would kill him. To prevent this, he killed the horse first. Some time later, a group of bandits attacked his house and killed him. But these were very poor bandits, unable to afford swords, and when they had happened to come across a pile of bleaching horse's bones...
However, it should also be noted that the Myrm's gridaksma blades only had bone handles: we can see from the game that the blade itself is metal. And, personally, I think the choice of handle was as much to freak out their opponents as anything else. :)
