Years after the events of End War, a new sentient robotic race called the Central Independent Systems (C.I.S.) entered and invaded the Korprulu Sector to strip mine the system's resources. With the Protoss being defenseless and assimilated by these cybernetic war machines, the Terrans and the Zerg must react quickly to a new threat. Which side will prevail?
To address the concern of mutalisk swarms in early-mid game and the ridiculous tech requirement of Silencers, Spider Droids have an anti air weapon separate from it's main anti-ground weapon. Compared to the latter the former deals normal but 15 less damage and attacks slightly faster.
This change makes Spider Droids strong against small air units like Mutalisks, but slightly weak to large units like the Battlecruiser and Warden.