It's Umbrella. Just to go over a few points of their "resume" of sorts:
-Spencer, the president of Umbrella, is essentially a power hungry trillionaire who wants to play God and believes himself superior to other humans, everyone and everything is disposable to him to reach his goals to live forever and take over humanity's evolutionary direction.
-The people who founded Umbrella alongside Spencer are no better and are a bunch of back-stabbing slimeballs who want a bigger slice of the Umbrella pie.
-They really don't give two shits at what their ambitions will cost, they actively began secret human experimentation almost immediately upon starting up their business. Men, women, children, elderly, even animals of all kinds, literally all life is disposable for their goals in Umbrella's eyes.
-Canonically they hired nazis to fund their continued human experimentation experiments, and Umbrella believes in "superior bloodline" and genetics, which is how the Wesker Children project got started (and it's not a coincidence Wesker and Alex were blue-eyed, blond-haired people before the virus injections).
-They accidentally made literal monsters out of humans with their experiments, and decided, "Hey, y'know what? There's probably a market for this!"
-Some of the things they did even to their supposed allies and friends are horrific. Case in point what they did to George Trevor and his daughter, Lisa.
-Have consistently shown they care a lot more about burying the truth than preventing any accidents from occurring. In Raccoon City they literally unleashed their most powerful B.O.W.s onto the town in their Tyrants and Nemesis to kill the remaining survivors and bury the evidence over anything else.
There's more to talk about in just how fucking evil they are, but they're not only evil, they're also greatly incompetent .
-They've had more than a few outbreaks of their terrible monsters and viruses starting great catastrophes in their wake.
-Despite trying to make B.O.W.s to be killing machines, how effective most of them truly are as weapons is quite debatable.
-Their tendency towards back-stabbing over loyalty leads to some of their key players, such as Albert Wesker, to jump ship. Or to actively kill their golden gooses, like they did with Marcus, just to claim their achievements as their own (some real ego on some of the people there).
-They go out in the most mundane way possible in universe (their company's stocks go under after Raccoon City).
-Their existence and downfall literally leads to a huge rise in global terrorism.
There's more, but yeah, they're the worst.
