Right from the start, Heart of the Swarm feels different than Wings of Liberty. Kerrigan is basically a monster goddess who can control millions of Zerg units (a.k.a. Swarm). This time around Blizzard wanted to give players that sense of absolute power. If Kerrigan tells her Zerg to die for her, they don’t get upset, they say “How many?” Now players will feel that responsibility of being the Queen of Blades.
12