The overlord of all the Control Brains, the machine behind the machines, the Master Control Brain is the ultimate authority for all that goes on in the Irken Empire. Residing deep within Irk's core, like some sort of horrible, bloated spider thing, the Master Control Brain commands the entire Irken Empire through its ambassadors, the Almighty Tallest. Though it usually delegates smaller tasks to the Tallest, the Master Control Brain can initiate a backup protocol, the Hive-Mind Protocol, which allows it to assimilate all non-defective PAKs at once, taking matters into its own hands. The downfall to this immense power, is - of course - the amount of processing it takes to run literally every operation that occurs within the empire. It is for this reason that the Hive-Mind Protocol is a last-minute resort only.
Nothing is known for certain about its early stages, or how old it is, only that it has been around since before the current Tallest were cloned. Like all other Control Brains, it is likely that the Master Control Brain started out as a PAK that was selected for upgrading into a larger form. Whether it advanced through the varying ranks of Control Brains or was simply programmed to succeed the previous Master Control Brain is unknown. Also unknown is what incident influenced it to have such a hatred for defectives (its most notable characteristic). It may be, however, that this passionate hate is simply part of its programming, as defectives are harmful to the Irken Empire as a whole.
The Hive-Mind Protocol Edit
The Hive-Mind Protocol was installed at some point during its reign as Master Control Brain. It is unknown how this protocol was installed. It is also unknown who conceived of the idea, whether it was another Irken or the Master Control Brain itself.
The Hive-Mind Protocol acts as a last-resort failsafe, in the event that the Irken Empire is threatened on a massive scale. It works by sending out a pulse from the Master Control Brain to all of the non-defective Irkens in the Universe. This pulse travels at speeds that are much faster than light, as evidenced during Invader ZIM: The DOOM Movie!, when all the targeted Irkens succumbed to Hive-Mind control within five minutes.
Hive-Mind influence is accompanied by the target Irken's PAK emitting large amounts of electricity for a brief period of time (usually 10 to 15 seconds). It is during this time that the PAK is being scanned for any potential defects. After the scan is complete and the PAK is identified as clean, the PAK glows green and the Irken's brain functions become absorbed into the Hive-Mind. In addition to the PAK glowing, the target's ocular implants emit a similar green light, and the target's voice adopts multiple tones. This may be an unintended side-effect of Hive-Mind influence, or it may be intentional on the Master Control Brain's part, to help intimidate any enemies.
The reason that the Hive-Mind Protocol is a last-minute resort only is because it saps processing power from other areas of the Master Control Brain's mind. This could potentially lead to lessened security and lapses in judgement, resulting in poor decision making that could be costly in the wrong scenario. The burden placed on its processing power also leaves it vulnerable to viruses or hacking programs, should any of its tracer signals be tracked back to their source.
The concentration required to maintain the Hive-Mind means the Master Control Brain must have a way to restore the Irken PAKs to normal. This is easily achieved. When Irkens who had previously been under the Hive-Mind Protocol return to a normal mental state, they tend to have bad headaches and are unable to remember anything from during the event.
It should be noted that all defectives are immune to Hive-Mind influence, as the Master Control Brain does not ping the PAKs of known defectives, for fear of cross-contamination. The Master Control Brain might hate defectives for this very reason: it cannot control them. Conversely, it may be that it refuses to touch defective PAKs because of how repulsive it finds them. Or it might simply be a measure taken during its programming to ensure that it does not become defective itself.