Comment on Aria Of War by ArtDoge

They are there in Heart of the Swarm and Legacy of the void campaign so they are a part of the universe even if they were scrapped from the multiplayer mode.

Warhounds were originally going to be a Terran mech unit in HOTS beta. It cost 150mineral, 75gas and 3 supply. It had an spell of missiles automatically at enemy mech units. It was later removed because Protoss had basically no counter(95% mech unit) and Zerg had no DPS powerful enough(220 HP)