Offensive Bias

"The metarch looms over us, a servant greater than its masters, and, I hope, untainted. Soon we will know."

- The IsoDidact musing on Offensive Bias just before the Battle of the greater Ark

Offensive Bias is a metarch-level Forerunner artificial intelligence. One of the few Contender-class ancillas, it was created to counter the rampant AI Mendicant Bias. It commanded the last of the Forerunners' defenses at the greater Ark and at the final battle of the Forerunners. While seemingly less creative and independent than Mendicant Bias, Offensive Bias was still capable of coordinating inconceivable numbers of ships, sentinels, personnel, as well as an original Halo and the systems of the greater Ark simultaneously. More importantly, Offensive Bias was designed to be far more methodically lethal than Mendicant Bias.

Fall of the Forerunners and firing of Halo
In the twilight hours of the Forerunner-Flood war, Offensive Bias was given charge of the last of the uninfected Forerunner ships and fleets. Shortly thereafter, Offensive Bias apparently took command of the defense of the greater Ark, the last large refuge of the Forerunners and many of their client species. It appears that the Forerunners accepted that only Offensive Bias was capable of matching Mendicant Bias's moves, as it were. As such, it was Offensive Bias who fired Omega Halo, by command of the Master Builder and then attempted to defend it against Mendicant Bias's Flood-crewed fleet, supported by star roads and other Precursor artifacts. It failed terribly, which may have fed into Mendicant Bias's disdain towards it, having previously referred to Offensive as an "inferior metarch". Such an attitude however, would only play into Offensive Bias's strategy.

Despite the devastating losses at the greater Ark, Offensive Bias was able to extricate a small number of warships from the destruction and make it to the lesser Ark. Before initializing the Halo's firing sequence with the IsoDidact, Offensive Bias announced that Flood forces were approaching the portal that led to the lesser Ark; simultaneously, Mendicant Bias sent a coded message to Offensive stating that it would give no quarter and would destroy the Ark. Mendicant offered Offensive a chance to join it and survive; Offensive rejected the offer and informed the IsoDidact of it, to reassure him that it was still free from the logic plague. Sharing all of its processes with the Ark's command Citadel, Offensive Bias then assisted the IsoDidact in preparing the Ark and Halo Array. Once the IsoDidact gave the order and the Array started to prime, Offensive Bias's attention shifted as it took the final Forerunner fleets to the Maginot Line to confront Mendicant Bias and prevent it from gaining access to the lesser Ark, its sole objective to buy time.

Even though Mendicant Bias's fleet outnumbered Offensive Bias's by 436.6:1, Offensive Bias was designed specifically to effectively counter and exploit Mendicant's rampant actions. During the battle, Offensive Bias played for time, allowing Mendicant Bias's rage to cause him to act irrationally and take its time in destroying Offensive Bias's fleet. After about eight hours of combat, the Array was fired which, aside from killing all sentient life in the galaxy, disabled the majority of Mendicant's fleet which was crewed by the Flood and out of its direct control. After the Halos fired, the advantage turned towards Offensive Bias: it had planned for the Halo effect, while Mendicant Bias had not, and nearly all its vessels could be commanded by it directly, including ones previously captured by the Flood. Within two minutes, Mendicant Bias was outsmarted and defeated by Offensive Bias, who utilized the now-crewless ships with a ruthless, unconventional efficiency, revealing its capability for methodical lethality. Mendicant Bias's fleet was annihilated and the rogue ancilla itself captured, its primary core delivered to the lesser Ark by Offensive Bias.

Zeta Halo
Around one century (77 years, in 97,368 BCE) after the firing of the Halo Array, and the subsequently mysterious survival of the Xalanyn after the event, the Grand Edict assigned Offensive Bias to Installation 07 alongside 117649 Despondent Pyre to guard the Xalanyn's prison.

Terminal logs
What follows is a logged transcript of events that occurred during and amidst the battle, as logged by Offensive Bias itself.

Trivia

 * In Halo 4, Offensive Bias' sigil appears on the Z-130 Suppressor Refractive skin, alongside the sigils of the Didact and Librarian.
 * In Halo 5 Infection games, if Exuberant Witness is selected as one's multiplayer announcer, she will declare the player as "Offensive Bias" if they earn a Zombicide medal.

List of appearances

 * Halo 3
 * Terminals
 * Halo 4
 * Halo: Silentium
 * Halo 5: Guardians
 * Halo Mythos
 * Halo Infinite