Originally Posted by
Neverafter
I guess it comes down to one of two options:
1) A blade was created (by someone/something) and at some point captured (at least in part) the essence of an Old God (or something that thinks itself on their level)
or
2) An Old God at some point was killed and all that remained of it was crafted into a blade
If 1 is true, then it would absolutely be possible to capture other entities of similar attributes. If 2 is true, then once the entity is freed, why should it be able to hold anything else? If anything, it would serve only to house Xal'Atath or Atath or whatever the entity's real name is. Why would it hold anything other than the essence of the being it was once?
Until more is known about the blade and it's capabilities, it just seems like a stretch for someone to capture an entity as powerful as an Old God, especially when it seems its the Old God giving Sylvanas directions on how to capture it.