Errors in the archives

Well, the "you" in Argent's speech is bolded, implying significance. I understood that as "you of all people should understand the power of this sword, since you first designed it". Also, if Argent meant the Kyuukyoku-Yaiba, it would have been much easier for him to just say "the sword you're wielding right now", since that's much more relevant.

Though the Eternal sword that never resurfaced again having been reforged into Ker's sword does make sense, too.