In addition to barb king and archer queen, how about a dark elixir hero like a gargoyle. A winged creature that favours defensive units. Because of its stone skin damage by tesla towers reduced by 50%. When at level 5 it's special ability would be that it can turn to solid stone. The gargoyle would crash to the ground causing splash damage to any building/troops in a 5 tile radius. It would stay there as it regenerated a portion of health. After regeneration it would lose its ability to fly and become a ground based attacker.
ability level increases would increase the speed and amount of health it regenerates.

