Beings of Tash Kalar
I hope you see the catapult.
It can shoot in any direction, except the ones blocked by its pieces. It can shoot over heads of enemy army, but it still needs to be in a straight line. On impact, it destroys anything, including a legend. And all common pieces around it. Color of the tokens does not matter. You cannot target an empty space, though.
It's pretty straightforward. Just prepare the pattern and you will probably find a suitable target. If you aim at a particular piece (especially a legend), you have to aim a bit, though.
It was one of the very first legends I have created. It had always this pattern, although originally, it included only two heroic pieces (wheels of the catapult) and killed only one piece. It was also rather orcish than undead looking.
But soon, it was decided the legends have to be more difficult to summon, more efficient... and look more epic.
Can you summon Bone Catapult on top of an enemy legendary piece and kill another legendary piece by its shot?