High Councilor Halogen was the longest serving member of the High Council in the last days before the Autobot/Decepticon War began. Rumor had it that he had personally known some of the Primes and had helped lead Cybertron through every major event after their era. His district included many of the less reputable parts of the planet, including Blaster City and the Badlands. His greatest political ambition was to annex the neighboring Hydrax Plateau. Unfortunately he'd been struggling to do this for so long that anything he said or did was immediately assumed by all to be a grab at the plateau.
Halogen was the duly-appointed moderator of the High Council on the day Megatron and Orion Pax came before them to argue for social change. Halogen demanded strict adherence to protocol and decorum during the hearing, sanctioning councilors and audience members alike for speaking out of turn. While he naturally expressed his abhorence at the terrorist violence being carried out by the "Decepticons", Halogen also seemed open to the idea of opening discussion on considering to reconsider the caste system.
A final decision on the matter of the castes was tabled, however, due to the more serious matter of Sentinel Prime's absence, and the lack of leadership for Cybertron. Based on previous discussions with the Hall of Records' chief archivist, Alpha Trion, and his own sincere speeches for the new "Autobot" movement for social change, Halogen represented the council's wishes to nominate Orion Pax as the new Prime: Optimus Prime. Megatron did not take well to this perceived slight and unleashed his fusion cannon, obliterating Halogen's podium (killing Halogen in the process) and effectively ending the Council session.