When I knew the new season is about crystal ponies, I think the boss has relationship with crystal, but I thought I'm wrong.... This is the boss in my imagination, well....so different with the real king sombra.
I feel this would be the true King Sombra. The one we saw in the show is just a pony this Sombra possessed. That would make for a great episode. You discover the Sombra killed by Spike was just a body possessed by a Evil Shadow Spirit named Sombra.