So, just what exactly IS this weapon that can kill off all three Originals left in the game?
That is the real question since we've had every piece removed from the table except for the possibility of a white oak stake found from a "not so dead" white oak tree... But, for now we will assume that Nature has made room for--or "allowed"--for a new way to be used against the Originals to kill them. I think the beginning of this season was very much on point with what we should expect from the ending, and even possibly the source of this weapon in the first place.
We spent the beginning of this season learning about the first vampires, the first progeny, born unto each of our Original main-stays: Klaus, Elijah, and Rebekah. How the Originals had no idea what their weaknesses truly were (other than the ones their mother originally knew and protected them from, like sunlight, and the knowledge of wood and the white oak), but they truly didn't know the true abilities that their dark gift had bestowed upon them. So, they slowly, yet surely, began to discover these new powers and how to use them with terrible intent or to help those in need.
This may be the very way that the Originals see their own end. An ability that they have never witnessed or tried has finally been discovered. A new magic, an unknown supernatural entity or creature... Who knows, but "something" is coming, the question is, just what exactly IS this "weapon". From what The Prophecy has said, it seems as though this weapon must be an artifact since it's used by multiple people. However, I wonder if there is any space for it to be either a new creature or simply a new ability (that vampires have simply never tried). An example for a "new ability" (or better said as something never tried...) might be the question, what happens when a human dies and has the blood of two (or more) Originals in them (or possibly even just ordinary vampires, though possibly from different sire lines)?
Could a new supernatural creature be born? A new type of vampire, that simply has the lineage of both (so, really, not that much of a change; though able to survive more than one Original dying, possibly). A vampire that craves and drinks vampire blood, immune to werewolf venom, but also closer to madness. Or a true abomination or a very NEW vampire species... Are there other unexplored abilities or even weaknesses that vampires have simply overlooked for the last 1000 years because it was too hard to accomplish--or too hard to find the ingredients (for example, if vervain makes a vampire incredibly weak, could there also be another plant or ingestible that would enhance a vampire; like Lucien's anti-werewolf venom, where did he get that; it is ALSO not something the Originals knew of...so it's quite possible that there is an ability that they themselves have never seen, but CAN use; much like Klaus having a child or his hybrids).
Could it be a new type of supernatural creature altogether? For example in the books the Kitsune are used and would be able to challenge an Original very easily. One scene in the last few episodes that made me wonder just what "might" be coming (if the "weapon" were a creature) was when Elijah questioned Shen Min about the "weapon". If you noticed, Shen was able to fight Elijah's compulsion on that question and was even able to kill himself before he divulged the answer. It made me wonder if another creature (or a witch) had already been over this subject with him and also wished for them to kill themselves should they be found out. Could it ever be that we will get a new family member delivered out of left-field, because if you remember The Prophecy does state that one of the killings will come at the hands of a family member? Right now I don't think any of the Mikaelson's would kill each either, but what if a new member came onto the scene--possibly someone that didn't even know quite who they were, someone like Henrik. One can wish... BUT, Shen did give us a clue. He DID indeed say, "they," when referring to who would have the weapon used against the Originals.
So we know that a group is behind this no matter what and I have a feeling that the originals will be facing this group down next season. This season they must try to protect themselves from the first blow and surprise attack that I don't think is truly from their progeny (though they are involved with BOTH sides of this affair--they are being used and may not have much of a choice in the matter). BUT, this is my idea of what is happening. I happen to think another side is involved especially since Shen tried to take out Hailey and I'm guessing it wasn't at the command of the Strix.
We do know that Aurora is backstabbing her two "partners". But, is it merely a means to an end--her ends. Or is she playing along with those two? Also, what IS Lucien doing with the land out in the bayou? Is there something out there that the Originals should be looking for? What is their endgame out there? Is it simply the place they wish to entomb their Sires if they decide to go and have a look-see (that seems the most logical to me) using that little magical Cursed object?
In the end what IS the "weapon"? Is it an artifact, like the white oak stake or Papa Tunde's pain blade, is it a new creature that we've yet to see in this series (and TVD), is it an ability or weakness that has simply been overlooked? What is the "weapon"? Either way, we already have ONE person willing to burn rather than tell them what it was AND another poisoned by (the one who is backstabbing and seems to be in more control than anyone else, that's right it's:) Aurora; Lucien's seer and witch.
What are your thoughts? What IS the "Weapon"?