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"Arise, my daughter. Arise... Kerrigan"

- The Overmind greets its newest agent(src)

Agent of the Swarm is the fourth zerg mission of Episode II of StarCraft.



During the zerg invasion of Tarsonis, the Overmind, the leader of the Zerg Swarm, found a creature that had the potential to become the Overmind's most powerful agent. This creature was encased in a chrysalis that would deeply infest it and transform it into a zerg. To safeguard the chrysalis during its incubation, the Overmind created a new Cerebrate with the sole purpose of protecting the chrysalis.[1]

As Jim Raynor and his forces traveled to Char and engaged the zerg, the Overmind told the Cerebrate to hold off engaging them. The chrysalis was about to hatch, and release the Overmind's most powerful creation on the galaxy.[2]

The Queen of Blades[]

Raynor's forces assaulted the zerg base, but to no avail. The chrysalis hatched, revealing Sarah Kerrigan, infested and transformed into a powerful zerg warrior. The Overmind announced her as its daughter, and Kerrigan declared her loyalty to the Swarm. The pleased Overmind ordered the Cerebrate to eradicate all terrans. Raynor recognized Kerrigan in her new form, and was horrified at what the zerg had done to her.

Kerrigan led the Cerebrate's forces against the terrans, and destroyed Raynor's command center.[2] Raynor confronted Kerrigan, who revealed she had psychically contacted Raynor and Emperor Arcturus Mengsk during her incubation,[3] and Mengsk had sent General Edmund Duke and Alpha Squadron to retrieve her. Though Kerrigan had the opportunity and ability to kill Raynor, she believed he was not a threat to her, and allowed him to escape with a handful of his men.[2]


The player must merely defend for the first ten minutes of the mission. The map is divided into islands, meaning the player must rely on air units and transports. Raynor will do likewise, and the player can take advantage of this using the queen's parasite ability. When parasite is used on Raynor's dropships, the player will permanently gain vision of them, allowing them to see when Raynor is moving his forces around and anticipate attacks. Raynor will attack using marines, goliaths, and handfuls of wraiths and siege tanks. The player can easily defend from these attacks with a handful of zerglings and hydralisks.

When the ten minute timer is up, the chrysalis hatches, revealing Sarah Kerrigan. She becomes controllable as a hero unit and must survive the rest of the mission, and the player receives the new objective to destroy or infest Raynor's command center. Kerrigan is a very powerful hero unit, and though she cannot attack air units, her ensnare ability is very effective against enemies of both types. With Kerrigan under their control, the player should easily be able to defend their base from Raynor's attacks and begin building up an attacking force. At this time the player may wish to expand to an island in the middle of the map that has a mineral field, but should bring defenders if Raynor attacks it.

Raynor's forces are scattered across the map, but the player only needs to destroy Raynor's command center to win. A flock of mutalisks can break the area's defenses, but the large numbers of marines and missile turrets in Raynor's base make them ill-suited for the attack. Instead the player should build a force of zerglings and hydralisks and load them into overlords with their ventral sacs upgrade. Once the mutalisk clear a spot for the overlords to disembark their passengers, the player can move in to Raynor's base and destroy his command center.


Starcraft - Zerg Mission 4 Agent of the Swarm


Strictly speaking, it is possible to win the mission by destroying Raynor's command center before the chrysalis opens. However, the time limit combined with the defenses of Raynor's base, makes this unlikely to do without using cheats. If this is done, the mission ends in the same manner.


  1. Blizzard Entertainment. StarCraft. Vivendi Games. Mission: Among the Ruins (in English). 1998.
  2. 2.0 2.1 2.2 Blizzard Entertainment. StarCraft. Vivendi Games. Mission: Agent of the Swarm (in English). 1998.
  3. Jim Raynor: "But the dreams... I dreamed you were still alive... that somehow... you were calling to me."
    Sarah Kerrigan: "I was. While I was in the Chrysalis, I instinctively reached out to you and Arcturus telepathically." StarCraft. Vivendi Games. Level/area: Agent of the Swarm (in English). 1998.