Complete Monster/Dragon Age

In a similar vein to that of The Elder Scrolls, The world of Dragon Age is filled to the brim with countless characters, be they heroic, villainous, or just about everywhere in between. However, just like The Elder Scrolls, it also has it's own share of characters who stand out from the rest for being completely and totally wicked with no chance or desire for redemption whatsoever, successfully disgusting all those around them by their sheer depravity.

Origins

 * In the Human Noble origin story, Arl Rendon Howe is notable for being the one who betrays and kills your entire family, including your young nephew and defenseless sister-in-law. When confronting him later, he mocks you about how he made your parents suffer before he killed them. He is also responsible for purging Denerim's elven alienage, resulting in the deaths of numerous elves, including an entire orphanage full of innocent children. It's also hinted that he helped Loghain sell said elves into slavery. This makes it just as satisfying to face him down as a City Elf as it is to face him as a Human Noble.
 * Bann Vaughan: in the City Elf origin story, he kidnaps the brides and bridesmaids of an Elf wedding and takes them back to his mansion to be raped -- and this isn't the first time he's done this, either. Leliana's Song has a moment where Leliana's crew overhear him preparing to torture/rape one of his maids because of a floor stain.
 * In the City Elf origin, when the local priest objects that he's disrupting a wedding, Vaughan tells her that if she wants to "dress up her pets" and play with them, that's fine with him, but she shouldn't expect him to act like it's a real wedding. Yeah, it's really hard for even a Villain Protagonist PC to avoid killing him in Arl Howe's dungeon on subsequent playthroughs, even if he is a vote against Loghain in the Landsmeet.

"Vaughan: Anyway, it's not like the Elves are real people."


 * The Awakening expansion pack gives us the Baronness, an Orlesian noble turned Pride Abomination who took her peasants' children to use in blood magic rituals. When her peasants revolted, she imprisoned them all in the Fade where she tortured them until the Warden and the Spirit of Justice came along years later.
 * The Dwarven Paragon, Branka. As part of a long and obsessive quest to get her hands on the Anvil of the Void, she went traipsing off into the Deep Roads with several hundred members of her household following her; there, in the act that unambiguously pushes her into "irredeemable evil" territory, she When you finally meet her, she actually complains that members of her household begged for death and claims that they had no right to protest her decision. Oh, and when she learns of the plight of Orzammar? She doesn't care one bit. It's All About Me is her hat.
 * The PC him/herself can be one, if the player wants to do it that way. Each of the main story quests presents the PC with an unambiguously evil way to handle the proceedings: defile the Urn of Sacred Ashes, allow the Templars to wipe out the Circle of Magi, talk the werewolves into slaughtering the Dalish elves, resurrect the construction of golems, a process which you were just told in graphic detail is a truly horrific Fate Worse Than Death, and take a bribe from the Tevinter magisters to let them get away with selling the Alienage elves into slavery. "The Arl of Redcliffe" takes the prize at this: you can leave the village of Redcliffe to be wiped out by The Undead, then choose between killing a child or using Blood Magic to make a Human Sacrifice to end the Demonic Possession, then (if the PC is a mage) make a Deal with the Devil to sell a young boy's soul in exchange for mystical power, wealth, or just some hot demonic sex. And that's just in the main storyline. The sidequests allow you to steal from widows, become a contract killer, break up a pair of Star-Crossed Lovers by seducing one out of their virginity and rubbing it in the other's face, and other bits of more mundane, yet still soul-crushing evil. You can be a bastard in this game.

Dragon Age II

 * Sers Otto Alrik of the Templars is everything Anders hates about the Order. He is a sadistic bastard who abuses the Rite of Tranquility by illegally Tranquilizing mages who passed their Harrowing, threatens more reasonable Templars who protest his deeds, and drafts a plan to make all mages in Thedas Tranquil. When you see him in "Dissent", it's heavily implied that he uses the Rite of Tranquility to make pretty mages into willing sex slaves.
 * Danarius. Quite apart from being a Magister of the Tevinter Imperium, which means he had to do some pretty despicable things to gain that position, he was the master of Fenris. Fenris fought for and won his family's freedom, so Danarius forcably engraved lyrium into his skin and knowingly removed all memories and desires that Fenris once had (which he will do again if he gets Fenris back from Hawke). When he escaped, Danarius ordered him to kill the warriors who had saved his life, knowing that he couldn't say no.
 * Through Party Banter, you find out that he once slaughtered a young boy at a party to show off his powers to the other Magisters.
 * And Word of God has confirmed that he sexually abused Fenris as well. Dear God...

Dragon Age Inquisition

 * The Elder One, aka Corypheus, is an ambitious being that will stop at nothing in his quest to become a god. One of the seven Magisters of Tevinter who invaded the Golden City in a bid to usurp The Maker, Corypheus was corrupted into one of the original Darkspawn as a result and is inadvertently responsible for the Blights that constantly threaten to destroy Thedas. Having failed and been punished for his attempt to serve a god once, he has decided to become a god himself by physically entering the spirit world known as the Fade and conquering the Black City. In his mad bid for power, the Elder One tries to murder Divine Justina, causes a Breach into the Fade to tear open in the sky which kills thousands and releases murderous demons into the world, tries to brainwash the mages to serve as his army, corrupts the Templars into insane monsters by feeding them Red Lyrium which is made from people he's captured and attempts to massacre the Templars at Therinfal Redoubt who haven't converted to the Red, attacks Haven and attempts to kill everyone within, and tricks the Grey Wardens into doing Blood Magic and Human Sacrifice to summon a demon army for him to use to conquer the world. In the end, after his plans are thwarted one time too many, Corypheus reopens the Breach to lure the Inquisitor to him, willing to destroy the world out of spite in the process.