The core matrix is the central power structure of Cybros, and maintains the other Purifier matrices in the ship, as well as keeps it in orbit. It can be controlled remotely. The core matrix also powers the weapon systems of Cybros.
During the End War, hybrid and the Amon Brood attacked Cybros intent on destroying the core matrix. Hierarch Artanis and his Daelaam forces defended the core matrix while destroying the null circuits keeping the Purifiers in stasis. After the Daelaam reactivated all Purifiers on the station Executor Clolarion took control of the core matrix, and used it to activate the purification systems of Cybros, purifying the moon Endion below it.
Defending the core matrix is one of the objectives of the mission "Purification." If it is destroyed, the mission ends in failure. The zerg will attack from multiple sides, so static defenses both in front of the structure and on the ramp above it are needed.