Sir Hugh Irons was one of the main Seated at the Convention of Twelve, along with fellow Knights Shelby Penwood (one of his oldest friends), Integra Hellsing (daughter of another of these friends, Arthur Hellsing), and another nine Knights sworn to serve the British Crown at all costs. He was a lifelong friend of Arthur Hellsing and Penwood, and all three were together a powerful force in England from their instatement as members of the Convention of Twelve. It was they who authorized the usage of a loyalist vampire to vanquish the Poland camp responsible for the Order 666 implementation. After the war, he seldom saw action, but retained a deep distrust of the agent paired with the vampire in the destruction of the Nazi camp, Walter C. Dornez; his suspicions were perhaps more than justified, seeing how the Major, the Captain and the Doctor all survived.
Much later in life, he was caught in a Convention of Twelve gathering at Hellsing Manor when the Millennium agents the Valentine Brothers attacked with an army of ghouls. When Jan Valentine reached the Convention boardroom, he was promptly shot at by all the members, Irons included. At the end, with the Hellsing ghouls lying in agony all over the place, he ordered Walter to ignore Integra’s command to put down these ghouls and demanded Integra do it herself, to which she reluctantly complied, executing the ghouls with Irons’ revolver.
He was also found outside of London upon the devastating Millennium attack, and approached a military detachment to inform himself of the situation in the city; he was thoroughly unsurprised reports indicated there was a possibility Integra held resistance within the city. Upon learning of Penwood’s sacrifice and heroism, he praised him, though he still thought he was a tad incompetent. He also commented on how he had seen Walter’s changes in behavior and strongly suspected him of collaborating with Millennium ever since he went to Warsaw in 1944.