I guess since I just talked about it. I'll restate my reliquary post from the other thread.
Each of these swords (according to [url]http://home.ix.netcom.com/~kyamazak/myth/roland/roland-items-e.htm[/url]) has a reliquary, that is, a slot for the containment of a relic of sorts.
As I stated above, though the parallelism begins to fall apart slightly, this could relate to the fact that the AIs are stored within compartments (I'm not sure about Durandal, but Cortana certainly is contained int his manner). Just something I noticed while going over the story.