Beings of Tash Kalar
The fact you may move another heroic piece, together with the fact you may summon heroic Drummer any of four spaces of its pattern, may be very helpful when summoning legends.
And finally, this is the only Highland piece that is summoned over another piece of your color (good for you if you can destroy an enemy piece on summon space using improvised summoning or War Summoner).
Also, graphically, I originally imagined big fat orc with a big drum or pair of drums hanging on his neck. Probably affected by some Warcraft/Warhammer archetypes :). I was using this googled image in my prototype:
But when David Cochard put the drums on a bear in one of the early drafts, I said - why not. It is this bulky shape, and when we have two eagles and two wolves, why not to have two bears in the Highland deck.