If you're rooting for Dahlia Hawthorne by the end of Phoenix Wright Ace Attorney: Trials and Tribulations, there's somethingseriously, seriously, seriously, seriously, seriously wrong with you. No other villain in the series cackled with delight at the prospect of forcing a 19 year-old girl who would never hurt a fly to commit matricide or tricking her mentally-disabled Woobie boyfriend into a suicide pact that she had no intent on fulfilling so she could avoid getting caught. It gets worse - she later poisoned the lover of the attorney Mia Fey when he got too close to her crimes, before she seduced Phoenix Wright as well. When her twin sister Iris fell for Phoenix, Dahlia accelerated her plans to poison him. When an ex-lover of hers tried to warn Phoenix, Dahlia electrocuted him to death and tried to frame Phoenix. Despite being executed, Dahlia returned as a vengeful ghost, aiding her mother to kill Dahlia's cousin Maya Fey solely to spite her elder sister Mia's spirit. Taking steps to manipulate her twin again to help with the murder, she came back from the dead to possess Misty Fey (albeit due to Misty's desire to protect her niece Pearl) and attempted to murder Maya, being stopped only by the intervention of Godot who killed her host. But despite this she became convinced that she had forced Maya to murder her own mother and caused her to commit suicide, which she gloated over to their faces. She's also a giant hypocrite; she shows nothing but disgust towards Morgan Fey because of the "petty revenge" that she was after, but at the same time, Dahlia was going along with Morgan's plan specifically in order to get her own revenge on Mia.
Manfred von Karma. An absolutely ruthless prosecutor who cared more about winning cases than serving justice, Manfred had a flawless, decades-long win streak thanks to using every dirty trick in the book to ensure a guilty verdict and thus ruining the lives of countless innocent defendants in the process, until defense attorney Gregory Edgeworth managed to (rightfully) have von Karma penalized for his illegal workings in the courtroom. Although Gregory still lost the case, von Karma was enraged by the black mark on his previously-perfect record. Unfortunately, right after the end of the case, an earthquake hit the building. It trapped Gregory Edgeworth, his nine-year-old son Miles, and a bailiff inside an elevator. As oxygen was beginning to run out, the bailiff panicked and attacked Gregory. Miles threw a piece of evidence from the trial at them to get them to stop fighting, which turned out to be a gun. The gun fired once, a terrible scream was heard, and then Miles passed out from lack of oxygen. Unbeknownst to the people in the elevator, von Karma had come across them. The bullet from the gun shot through the glass and hit his shoulder, causing him to scream. In revenge for the black mark against his record, von Karma picked up the gun and shot the unconscious Gregory in the heart. Afterwards, von Karma took Miles under his wing and, for fifteen years, raised Miles to be the antithesis of everything that Gregory Edgeworth was, twisting the boy to fit his views and become a ruthless, cold-hearted prosecutor who cared for nothing but getting a guilty verdict every time. Finally, on the very last day before the Gregory Edgeworth murder case was closed forever, von Karma set up a murder and pinned the blame on Miles Edgeworth, intending to have his own foster-son executed for a murder he didn't commit. Von Karma also planned it out so that Miles would be convinced that he himself was the one who had killed his father and would confess to and be charged with that murder as well.
A minor point, but Von Karma was legitimately unaware of the fact that the particular piece of evidence that Gregory objected to was illegal. This does not change the fact that he had and continued to use other pieces of falsified evidence.
Redd White (Also from the first game) seems like a flamboyant, clownish buffoon on the surface, but in reality is a money-hungry, self-serving, absolutely ruthless weasel of a man who is responsible for the suffering of countless people. His company Bluecorp specializes in digging up dirt on influential people such as celebrities, members of law enforcement, and other such people so Redd can relentlessly hound them to do his bidding for the sake of boosting his ego, ruining their lives to the point to where a number of his blackmail victims have committed suicide. He doesn't care that his blackmail often leads to suicide, and continues with it in the present day with men like Marvin Grossberg. When Phoenix's mentor Mia Fey was in the middle of collecting evidence to take Redd to court with, he caught on to her and savagely murdered her, going on to pin the blame on her teenaged sister Maya and later on Phoenix himself just on word alone thanks to his connections with law enforcement. Not just responsible for the direct death of a good woman and ultimately responsible for countless other lives lost, Redd also ruined the name of the Fey clan of spirit mediums by leaking information of Mia's mother's involvement with the police to the public. Thanks to his colossal ego and lack of empathy towards anybody else, Redd has ruined countless lives with his absolutely toxic personality in pursuit of money and power.
Despite being on the lower end of the Complete Monster totem pole, Matt Engarde is still widely considered to be among the most evil people within the franchise for good reason. There is no motive given for the atrocities he committed (outside the murder), leading some to believe he did it For the Evulz. These atrocities are throwing away his manager Celeste Inpax (who he knew loved him) like a used tissue, and when she fell for his rival and got engaged, he told him that he was previously intimate with her in the hopes this would cause him to call off the wedding. It worked: Celeste Inpax was so heartbroken that she committed suicide and as a result Engarde was overjoyed. Of course, he doesn't just stop there. When he found out his rival now plots with his new manager, Adrian Andrews, against him, he hired Shelly de Killer to kill his rival, but still puts in extra plans to blackmail the assassin despite De Killer having nothing but absolute faith in him. Oh, by the way, he also laughed when Shelly de Killer kidnapped Maya and starved her so Phoenix Wright would become his attorney and get him acquitted for his crimes by threatening to have Maya killed if he didn't. Then he let Phoenix PIN the blame on Adrian, already an insecure, miserable woman who has attempted suicide in the past. The knocker for this is because Engarde probably knew about Adrian's past and still did it for extra lulz.
Kristoph Gavin in Apollo Justice. When one of his clients summarily dismissed him after a game of poker, he took it rather personally. So personally, in fact, that he didn't just ensure the man's case was lost - he got the lawyer defending him (Phoenix Wright himself) disbarred using some evidence that he had ordered forged for his own trial, then tipping off the prosecution that it was a forgery. This, on its own, would only qualify him as a Magnificent Bastard, but there is more to the story. There were several loose ends to clear up, including the defendant's disappearance. First, he staged an attempted kidnapping of the forger - a sheltered, timid twelve-year-old girl by the name of Vera Misham - and then, when it left her too traumatized to go outside, he stopped by and gave her a good luck charm of a bottle of clear nail polish... which had a painful, extremely virulent, slow-acting poison in it. Kristoph had noticed her habit of biting her nails when nervous, so surely that would take care of her if she was ever pressured about what he'd had her make. He also took great pains to make sure her father Drew would die as well by placing a stamp with the same virulent poison on it and ensuring that he'd have to use it in order to send a specific letter. And as a result, Drew died and the now-nineteen year old Vera slipped into a coma and almost passed too. He then meticulously kept tabs on everyone who had been involved with the case for seven whole years to make sure nothing went wrong - including befriending the man whose career he had ruined. And if that man hadn't been Phoenix Wright, he probably would have gotten away with it all.
Don't forget his cold-blooded murder of Zak Gramarye/Shadi Smith over a seven year old game of poker that Kristoph lost. Sure, the guy may have been a jerk, but he certainly didn't deserve to be beaten to death with a thick bottle...
What really seals Kristoph's status as a monster is that he is like a combination of Dahlia Hawthorne and Quercus Alba: he cares nothing for anyone else but himself, he sees other people only as tools, and he will carry out whatever atrocious deeds he feels serve his own interest. And he's not just completely without remorse, but disgustingly smug about the lives he ruined due to his machinations.
Investigations has Quercus Alba, the corrupt ambassador of the country of Allebahst and the head of a large smuggling ring whose criminal activities have resulted in the country of Zheng Fa being driven to economic ruin. The other criminals of the game (except Lance, though his dad IS one of Alba's lackeys) answer to this guy. He is the one who ordered the deaths of Cece Yew, Deid Mann, and Byrne Faraday and killed Mask*DeMasque II and Manny Coachen with his own hands (well, with a statue and a knife, but you know what I mean). His reasons for these killings are as follows: Cece Yew and Deid Mann were witnesses who needed to be silenced, Byrne Faraday was a member of the Yatagarasu whose goal it was to expose his operation, DeMasque II was going to steal his fake statue and, with it, some plates used for a large-scale counterfeiting operation, and Manny Coachen because he ordered DeMasque II to steal it. Manny ordered the theft because he was planning to betray and usurp Alba and was unaware that the fake statue had been switched with the real one. He almost gets away with it due to Diplomatic Impunity, too. Also, confronting him and getting him to admit to his crimes is...difficult. And lengthy.
Arguably, the worst part about Alba is not so much his killings or even the reasons for them, but the fact that under his facade of a kind old man lies a sociopathic monster who has no remorse or regard for human life, which Edgeworth is disgusted by. In his own words, the question of if all lives hold meaning "Doesn't even warrant an answer."
Investigations 2 has the elderly Psychopathic Manchild Blaise Debeste, the corrupt chairman of the Prosecutorial Investigation Committee (as well as the former chief prosecutor) who gleefully drops casual death threats, suckers defendants into making plea bargains only for him to screw them over by sending them to rot in prison for life, and makes a living auctioning off crucial evidence on the black market. Blaise sided with the Bigger Bad of the story to assassinate the real president of Zheng Fa years ago and killed the reporter that witnessed the murder. Later on, he killed the reporter's girlfriend and framed Kay for it. He also gave Manfred Von Karma the only penalty he ever got because he was caught forging evidence, despite the fact that Blaise helped Von Karma with the evidence and is thus responsible for the DL-6 incident that shortly followed, with Gregory Edgeworth's death, Yani Yogi's life being ruined, and Miles Edgeworth's horrible upbringing are all indirectly resting on his shoulders. Additionally, he blackmails many characters in the series to work with him if they value their lives which include tampering with the crime scene and hiding crucial evidence. He even blackmails the judge Justine Courtney to get her to work against Edgeworth because he kidnapped her adoptive son.And let's not get started with the traumahe puts his son Sebastian through the entire game, who he constantly berates and tells in the worse way possible that all his achievements were because of his connections (and knowing that Bansai has a lot of connections with shady folks, one can only imagine what would have happened if they didn't comply) and not from Sebastian's hard work. Later on, he kidnaps his own son (but, to be fair, he was aiming for Courtney's son), and when Sebastian finally snaps out of his Heroic BSOD thanks to Edgeworth, when he tries to confront his father, he proceeds to humiliate his son even more in court to the point of disowning him in front of many people. And to top it off, it's hinted that he has both murdered his own wife and sexually abuses his son. This sicko is even worse than Von Karma.
The nameless spy known as the Phantom, who spends most of the game impersonating the late detective Bobby Fulbright in Dual Destinies is extremely nasty and the second figure (after Kristoph Gavin) responsible for ushering in “The Dark Age Of The Law.” He started off by disguising himself with a mask he found and killed Athena Cykes' mother Metis when she was only 11 years old, in front of her no less, and ended up getting Prosecutor Blackquill convicted. Before that, he killed the real Detective Bobby Fulbright and assumed his identity. He also sabotages a national symbol of pride, known as the HAT-1, a rocket, almost killing the astronaut on board. He also killed Apollo's best friend since junior high, Clay Terran, because Clay almost revealed his identity. If that wasn't bad enough, he's ruined the lives of several people besides the aforementioned Athena Cykes and Prosecutor Simon Blackquill and is indirectly responsible for almost every murder in the game, including setting off the bomb in the courtroom that was thought to be the work of Ted Tonate, which could have caused massive amount of death. Oh, and he framed two girls ( Athena and her best friend, an Ill Girl), the aforementioned Prosecutor Blackquill, and an astronaut for his crimes. To top it all off, if you count the murder done by his associate, Ted Tonate, he has the highest death toll of the entire franchise. He's not sorry for any of this, folks. What's really disturbing is that nobody knows his true identity. He also doesn't feel emotions the same way "normal" people do. Because of this, he is a chillingly realistic version of a sociopath in a video game.
A nasty little detail that really emphasizes his monstrous nature is the fact that he gets to serve as Blackquill's handler while the disgraced prosecutor takes a case. He uses this as an excuse to tase the hell out of Blackquill under the pretense of over-enthusiastically keeping a convicted killer in line. In reality, this serves little purpose but to kick an innocent man who's already endured horrible suffering when he's down.
The heartless and egomaniacal Ga'ran Sigatar Khura'in is the figure responsible for ushering in the kingdom of Khura'in's equivalent to the Dark Age of the Law. A woman born to the royal family yet possessing no spiritual power, Ga'ran was passed over for the throne in favor of her kind and gentle sister Amara. Jealousy and hatred towards Amara led to Ga'ran making an attempt on her life by setting her residence on fire. In the chaos, Ga'ran murdered the musician Jove Justice and left his infant son to die, then went on to frame the lawyer Dhurke Sahdmadhi for Amara's death. In the wake of the queen's assassination, Ga'ran's actions led to the passing of the Defense Culpability Act, which would force defense attorneys and anyone associated with them to suffer the same fate as the accused, which led to the deaths of thousands of innocent defendants and lawyers alike, and in the present day lawyers are all but extinct and the accused are helpless against the prosecution. In the meantime, Ga'ran is keeping Amara hidden away and forces her and her son Nahyuta to cater to her every whim on threat of ruining her daughter Rayfa's life. Ga'ran, finding out that her husband Inga is planning to overthrow her, without hesitation kills him and frames Dhurke for it. During Dhurke's trial, Ga'ran takes up the role as the trial's prosecutor and wastes no time in doing the damnedest to win the trial and get anyone who showed support for Dhurke executed under the DC Act. When it becomes apparent that Dhurke isn't the murderer thanks to Apollo's efforts, Ga'ran tries to throw Amara under the bus and has her shot when Apollo proves otherwise. When the court reconvenes, Ga'ran forces Nahyuta to take the fall instead, and, once backed up against the wall by Apollo, she passes a law that makes standing up to her punishable by death and tries to have him, Phoenix, and Nahyuta all executed on the spot for defying her.