I find it tough to believe that if you were who you say you are, you would tell us that there is a Z legendary. I mean, yeah, we are kind of expecting it, but that's still a big thing to give away.
To be fair, I myself do not know for sure that this is the "Z" legendary, but based on the obvious trend and the fact that it is a legendary with an obvious Z-like shape, I strongly believe this to be the case.
"I need a legion of 300 chickens, about yey high, to be lit afire and catapulted at our enemies on the eastern front!!"~Aragorn, Return of the King