On a similar note, Phoenix, Edgeworth, and Gumshoe are all varying degrees of nice and personable. But if you committed murder they WILL find you guilty. When Maya's life was at stake Gumshoe became competent. GUMSHOE.
This is in fact a major part of Edgeworth's Character Development: he started out as a brilliant prosecutor who did not care if the people on trial were actually guilty; and he managed to win every single case before meeting Phoenix in court. He then realized that a "guilty" verdict is not the most important thing in the world. But if he knows you actually did commit a serious crime, not even Phoenix Wright can save you.
Hatoful Boyfriend: The gentle narcoleptic teacher Nanaki Kazuaki turns out to be Cute But Psycho in the "Bad Boys Love" route, as well as an identity thief who betrayed and murdered the original Kazuaki, as part of his plot to get revenge for his dead childhood friend Nageki. During BBL, he pulls a gun on the characters, then tries to murder Ryouta for his liver. Possibly an inversion, since it seems the "kindly teacher" persona is a facade.
In the sequel Holiday Star we learn that the original Kazuaki is not immune... not since he became The King.
Yuuya is no slouch in the original game, either. Initially seen as a friendly, harmless, Chivalrous Pervert, he reveals in "Bad Boys Love" that he's perfectly willing to kill, he dismembered the human girl, and in the backstory, he crushed an egg belonging to his stepfather, which is basically infanticide.
Beware all the nice ones in Nine Hours, Nine Persons, Nine Doors. In particular, hurt either of the affable and helpfully sharp Brother-Sister Team of Snake and Clover and the other will rip you to a ragged pile of shreds on the spot; bumbling Big Guy Seven is a former highly successful Cowboy Cop detective and rescued the players of the first Nonary Game singlehandedly; soft-spoken, peaceful, cute-as-a-button Love Interest June is in fact Zero and the game's chessmaster; and even jokester everyman protagonist Junpei is quite an expert Guile Hero when he needs to be.
Accel in SC2VN is the nicest and most caring player that you meet. But when his coach blames him for his team's loss, he willfully abandons his team mid-contract, knowing full well how much drama this will cause.
Yo-Jin-Bo could arguably apply this trope to all the guys except Ittosai. However, special mention must be given to both Bo, the highly chivalrousBishounen fond of kissing your hand, and Mon-Mon, the goofy monk. Bo cuts Nobumasa in half vertically and Mon-Mon punches through his chest and crushes his spine. Ouch.
When Aeka told Antoinette to kill her in Yume Miru Kusuri to just get it over with and kill her already instead of needling her, it wasn't her being suicidal. It was a warning that if you keep pushing her she's eventually simply going to snap. The route ends with Kouhei taking down the gang trying to rape Aeka single handed before he starts strangling Antoinette. Aeka tells him to stop... so that she can do it. They throttle her together until she shits herself at the verge of death, both unwilling to take more abuse from her and wanting to end it here.
In Aya's epilogue for Akatsuki No Goei, her father finally finds out about her relationship with Kaito and tries to fire him. She instantly grabs his arm and shows that Boobs of Steel is actually quite consistent by nearly breaking his arm before he agrees to hold off on a decision temporarily. Further, the robot Yuuki is the most easygoing of the bodyguard class, but he's still a robot. Even Tominori quickly caves in when he makes Yuuki mad. Notably, Yuuki is the one person Kaito quite possibly could not beat in a fight.