Momma always said war was like a box of chocolate. You never know what you're gonna get.
How the heck has nobody talked about this guy already?
What's the Work?
Hellsing is a series about a group of vampires called the Hellsing Organization protecting Britain against supernatural monsters created by Nazi propagandists called the Millennium Organization.
Who is the Major? What has he done?
The leader of Millennium, the Major (or Montana Max or Sturmbannführer) was a Nazi survivor of World War II who was part of a project to turn people into vampires to turn the side of the war in the Axis' favor. Once the Allies invaded Nazi Germany to reclaim Europe and a young Walter Dorneaz and Alucard, a rebel vampire created from cloning the legendary Dracula, attack the Millennium headquarters, the Major and his subordinates escaped to South America to continue their research. To the modern-day, Millennium continues making vampires and other supernatural creatures in secret by conducting brutal experiments on human test subjects that painfully turns them into monsters.
So the goal for the Millenium was to ensure Germany's victory in WW2 and establish a Reich to last for a thousand years (hence Millenium). But the Major has different plans in mind. Essentially, he's a war fanatic who plans to start another World War not for global dominance or any other purpose, but for the fun of it. There is no end to his war in mind, he just wants to cause as much carnage as possible, destroying everyone until there is nothing left to oppose him and Millenium, aka human omnicide. The really messed up part behind it all is that the Major has no motive or purpose behind his goal, he's doing it all just for the thrills and his love for war.
Once his army is settled, the Major sends his supernatural monsters to London to fight off the only ones who have any chance to stand against Millenium, the Hellsing Organization, having his monsters slaughter countless innocent people to draw them out (NOT EVEN BABIES ARE SPARED!!!). The Major, of course, shows no remorse for what his men do nor how many people they have to kill to reach the rebel vampires. When one of his officers objects to the Major sacrificing their soldiers carelessly, he has him executed on the spot just for saying that.
In the end, the Hellsing break through the Millenium base and blast the Major's left side off, revealing himself to be a cyborg. Integra debates if he was a monster himself or not, but the Major assures her and Seras that he has always been a human as long as he existed. Integra finishes off the cruel Major for good via a bullet to the head; but in the end, the Major got exactly the fate he wanted, to die at the end of his "great" war.
Migitating Factors
He wants to plunge the entire world into an endless war for the fun of it showing no care for anyone who suffers from it including his own men. He's also aware of his crimes and doesn't care. Enough said.
Heinous Standards
Alright, now I do know that the world of Hellsing is dark... extremely dark. Heck, it's probably up there with the likes of Berserk, Attack on Titan, and Elfen Lied as the most crapshoot manga of all time. In a world where a majority of the villains are all psychotically sadistic to the core, even anti-hero Alucard is willing to go past the standards judging the extremely cruel way he tortures Rip Van Winkle to death. However, even with all that, the Major still stands out as being both the direct and indirect mastermind behind so many of the atrocities that have happened to the characters. If it wasn't for him and his endless war plans, there's a good chance that everyone would be living happier lives.
Also, surprisingly, the Major never commits a Moral Event Horizon... because everything he does is beyond redemption, committing atrocity after another just to show how much of a crazy mofo he is. While he's mainly non-action, his cruel rule over Millenium and the entire world for that matter outlive any spec of empathy to find for this guy.
Verdict
C'mon guys, it's pretty obvious where this fat warlord belongs.