The Defiler Mound is an essential high-tech building for the Zerg. The Defiler Mound requires a Hive to be existing before it can be morphed. The Defiler Mound allows the creation of Defilers, a unit of vital importance in certain match-ups.
The Defiler Mound does not build any units directly, but rather enables Defiler production at the Hive. Various upgrades affecting the Defiler can be researched at the Defiler Mound. These upgrades are:
- Consume, which allows the Defiler to replenish Energy
- Plague, which deals significant damage to the affected units and buildings
- Metasynaptic Node, which increases the Defiler Energy limit
In most match-ups, Consume is the commonly the first ability to be researched, enabling the Defiler to apply the additional Energy towards casting Dark Swarms. Consume will effectively allow a Defiler to have an infinite supply of Energy.
The Defiler Mound, as a Hive-stage building, is usually build in the mid to late game.
In the ZvT match-up, the Defiler Mound is usually built the earliest compared to other match-ups. In professional competition, the Defiler Mound can be seen being built within the first ten minutes of play, as the Zerg player staves off Terran Bio army with Mutalisks and Zerglings in rushing toward the Hive stage. Construction of the early Defiler Mound and Defiler enables access to the powerful Dark Swarm spell, which is vital in significantly increasing the life spans of attack units placed under the Swarm. It is most often used to protect Lurkers and Zerglings against Bio Terran forces including Seige Tanks. In this match-up, the Zerg player will also research Plague against the Terran forces, as well as the Metasynaptic Node to maximize Energy available for casting powers. Because of the many effective abilities of the Defiler and the generally low hit points of the Defiler Mound, the structure is commonly targeted in a dropping attacks.
In the ZvP match-up, the Defiler Mound is generally built in the late game as part of a Ultralisk/Zergling strategy, providing the Zerg units Dark Swarm cover, which is effective in countering the Protoss opponent who opts for a sizable number of Dragoons.
In the ZvZ match-up, the Defiler Mound is generally not built, as this match-up rarely proceeds to the Hive stage.