Arthur Hellsing was, before anything, a man. A man of many vices and many indiscretions, who nonetheless managed to increase the Hellsing Organization's influence beyond its primitive scope and allow for further expansion. Educated at Balliol College as a descendant of Abraham van Helsing, he was assigned a young butler who had also spent some time in that school: Walter C. Dornez. Arthur, during WWII, developed a severe case of borderline alcoholism and unquenchable lust for carnal pleasures, and with the influence he commanded, he very rarely denied himself these desires. Despite this, he held a firm hand upon the estate's resources, and was eventually entrusted with the family seat at the Convention of Twelve and the knowledge of the loyal Nosferatu sworn to obey his orders without question. Catankerous and outspoken, he never feared voicing his opinion without remorse or concern. His main friends, through all his life, were Sir Hugh Irons and Sir Shelby Penwood, both of who held similar chairs in the Convention of Twelve. Their group was thus a formidable power source in the British Empire of WWII.
Midway through WWII, Arthur and his friends started receiving accumulating rumors of horrors unspoken in a Polish camp where a mysterious Projekt, Order 666, had been issued. Words of secret experiments and undead monsters became serious enough to convince the trio to authorize the deployment of a higher class of weapon to combat the burgeoning threat: the Hellsing monster. Pairing him with Dornez, Arthur ensured the destruction of the camp though he was unaware of a mysterious circumstance, as of yet unrevealed, that allowed for the Projekt main three figures, the Major, the Captain and the Doctor, to survive the carnage virtually unscathed, a circumstance that had much to do with Walter. Some time later, he grew weary of Alucard, believing him too strong a weapon to be solely relied upon, and had him sealed and any records of his existence cloaked or destroyed to continue the Organization's work through more conventional soldiers. He retained Dornez as a butler and eventually promoted him to retainer of the family.
Eventually, he somehow found a woman who he found good enough to become his wife, and sired a single daughter, Integra. His brother Richard tolerated his excesses in the hopes of reaching the power Arthur enjoyed. His wife died before Integra was twelve, and eventually his lifestyle caught up with him and caused to start slipping into a deep sickness. He revealed to Integra in hushed tones about Alucard's existence and resting place, and tried to ensure his power was passed down to her. Richard found this unbearable and attempted to kill her only to set in motion the events that led to the genesis of the Hellsing manga.
By all means, Richard was not a perfect man. Obnoxious, drunk, loud and outspoken, not many liked the odd Hellsing heir. Even his close friend Sir Shelby Penwood would later admit to Integra he found himself occasionally fastidiated by Arthur's now and then over-the-top demands for weapons, alcohol and fun, and while Sir Hugh Irons recognized him as a great man, he also commented he had been a fool for trusting Walter, foreshadowing his role in the Final Night of London.