I think by now, we've given our theories who they are, but what do they want, what are they trying to accomplish and are they the worse threat the spinx prophecised?
This one should be an easier time figuring out cause they arent a ton of villian plans out there, i think we can assume its a villian plan on a global scale
So ill go through them
Total extinction of all supernaturals and possibly humans-again this has triad all over it but they could very well be working for triad again
Enslavement over the world-forcing them to do things they dont want or just to make them suffer in a physical way
Finally they could very well be trying to resurrect someone or someones(and unless its a suprise then im taking out the main characters of tvd and originals so sorry no stefan or klaus)
And we know their plans involve the malivore symbol, the malivore pit, a zombie minion and they want ryans body and it may have something to do with the salvatore crypt cause a fan pointed out that i didnt even notice, the zombie and red hood were dragging ryan into that crypt. But I think the only people who are in there are again stefan, lily, giseuppe, zach, the rest of the family(except silas, he is buried in the woods) and maybe stefan and damons half brother. I really hope their plans arent to resurrect a former salvatore member, but with the fact stefans library just happened to have malivores knife, it makes you wonder if the family had more to do with malivore than we suspect.