Complete Monster/Dead Rising

The Dead Rising video game series gives us plenty of these, going out of it's way to show us that the real monsters aren't the mindless zombies, but thinking, rational human beings.

Dead Rising

 * The first game has Jo Slade. She rapes and beats women to death with her nightstick for fun, and gets incredibly pissed off at Frank West for ruining said "fun". To make things worse, one of her hostages says that there were plenty of other girls being held captive by her that already died before Frank showed up... it's also worth mentioning that during her boss battle, she'll actively torture her hostages in the middle of the fight after flooring you with her tazer. Keep in mind, most psychos tend to leave their hostages alone and go after you and any survivors you've bought along to help during their fights.

Dead Rising 2

 * Tyrone King in the second game is a smug, greedy game show host who starts the Fortune City outbreak at first to obtain a large sum of money for Phenotrans, and also uses the outbreak as a means to be able to loot the entire city's casinos while framing his employee Chuck Greene for this in order to cover his ass. Later on in the game he gets bitten by a zombie, and Chuck is able to save his life and give him Zombrex to repress his zombification. How does TK thank him, you ask? . Ungrateful Bastard doesn't even BEGIN to describe him. Really, T.K. is just a repulsive, greedy bastard all around who doesn't give a damn about all the lives that are lost during the outbreak he started as long as he can run away with cash in hand.
 * The Dead Rising 2 DLC Case West brings us the ever so lovely Marian Mallon. A horrifically selfish and misanthropic woman with a colossal ego, Marian is the head of a corrupt pharmaceutical company called Phenotrans, and orchestrates zombie outbreaks such as the one in Fortune City in order to harvest parasitic wasps used to create (and drum up interest for) Zombrex, which temporarily keeps a zombification victim's condition at bay. Not only does Marian have no problem whatsoever with killing thousands of people for profit, but she also constantly drains away at the wallets of the many people afflicted by the bites since Zombrex merely keeps the condition at bay for 24 hours which causes them to have to buy the medicine on a regular basis. Infuriatingly, Marian refuses to make a proper publically available cure for zombification that can free these people from their condition, and justifies it by saying that she is the only person worthy of being cured, and that humanity bought this dangerous disease on themselves for their inherently greedy, selfish nature.
 * She reappears in the third game, where she also orchestrates the Los Perdidos outbreak alongside fellow monster General Hemlock so she can find the person whose blood holds the cure to Zombification (presumably so she can cure her own condition, given that she previously viewed humanity as being unworthy of a cure). Whenever she captures Nick Ramos and his friend Diego, she tries to find out which zombie infectee is immune by preparing a laser that accelerates zombie parasite growth . And anytime we see her interact with anyone, even Hemlock, she does nothing but act like a colossal bitch and is prone verbally abusing Hemlock

Dead Rising 3

 * The third game is Darker and Edgier than the previous installments, so it should be no surprise that it has several of it's own monsters as well. One good example is probably the most terrifying example in the series: Albert Contiello, a sadistic and greedy surgeon who slices open innocent people (without painkillers, mind you) in order to harvest their organs for a profit on the black market. He also injects Nick Ramos with a drug that causes him to hallucinate and see Albert's hostages as clones of him, potentially putting them in danger during Albert's nightmarish boss fight. And like Jo from the first game, he goes out of his way to torture his hostages during his boss battle by hacking at them with his surgical saw.
 * As one would expect from the military's top brass in this world, General John Hemlock is an incredibly vile person. He's meant to be a grim military official who wipes out civilians during zombie outbreaks so any truth about the government being involved to an extent is silenced. But unlike Brock who at least is content with his station, Hemlock is a complete and utter bastard with no loyalty towards anyone. He He then takes command of Los Perdidos through martial law while ordering his sadistic right-hand woman Hilde to hunt down and kill any stray survivors whether they pose a threat to his plans or not. But it gets even worse when he reveals to Marian Mallon, the CEO of Phenotrans . All in all, Hemlock has an insatiable lust for power, and he's more than willing to crush anyone who gets in his way to personal glory without a second thought.