Some anime characters have a "loose" relationship with the truth. This is a polite way of saying that some characters lie as naturally as they breathe. These anime liars will bend the truth so that they can manipulate others for personal gain, keep dangerous secrets, or appease a deep-seated emotional need. No matter what their reasoning is, anime characters who lie regularly can add much-needed tension to an otherwise commonplace story.
When a particularly untrustworthy character steps on-screen, viewers are left to wonder how and when the liar will get caught, and what the wide-reaching effects of the deception will be. Depending on the situation, one might end up loving the character for their crooked ingenuity, or one might just want to throw them out a window for being so terrible. Either way, these characters add spice to the story.
Death Note is full of liars, but the biggest by far is Light Yagami. Light doubles as the mass murderer publicly known as Kira, and uses a magical notebook to end the lives of criminals. Originally, Light's goal is to create a safe and just world, but his drive quickly morphs into a megalomaniacal desire to become a god.
In order to achieve his villainous ends, Light has to lie constantly to avoid being caught. Whether he's claiming to be vehemently against Kira's actions, making up alibis to cover his tracks, or telling his mother that he's studying when he's actually on a snack-fueled murder spree, just about everything that comes out of this guy's mouth is a lie.
School Days is notorious for being one of the most disturbing anime ever. Seriously, the show ends with Makoto Itou getting his head chopped off by his enraged ex-girlfriend, Sekai. What could possibly motivate Sekai to carry out such a brash action? For starters, Makoto acted dishonestly throughout the whole of their relationship.
Makoto claims to love Sekai — even though he clearly does not — just so she'll sleep with him. After dumping Sekai for Kotonoha, Makoto pretends like his relationship with Kotonoha has ended (even though they're still very much together), just so he can have another shot with Sekai. Makoto doesn't have the guts to honestly discuss his feelings, so he opts instead to lie manipulatively.
Kyuubey of Puella Magi Madoka Magica engages in a specific sort of lying: lying by omission. While Kyuubey does not outright lie to the young magical girls he tries to coerce, he only provides them with details he thinks they'll find persuasive. Conveniently, he always leaves out the aspects of being a magical girl that seem unsafe or unpleasant. Kyuubey belongs to an alien species that can't feel or understand human emotion, so it feels natural to him to prioritize efficiency over the feelings of the people he deals with.
Reigen Arataka of Mob Psycho 100 will lie about pretty much anything, as long as there's some way to make a profit. He claims to be psychic, and makes a living off of exorcising ghosts. Instead of actually leading the exorcisms himself, he employs a 12-year-old boy who goes by the nickname Mob to handle the entrenched spirits. How does he convince Mob to do this work for minimal pay? By making it seem like he can train the youth to use his powers more effectively.
While Reigen is unquestionably a con artist, he's also oddly moral. He can't really teach his young employee how to use his powers, but he nonetheless acts as a mentor figure for Mob. When the boy needs help rescuing his younger brother from powerful kidnappers, Reigen steps in without hesitation. Even though he knowingly lies about his abilities, he believes that adults have a responsibility to look out for children.