Now that Anagram is past Case 2, I can talk about maybe my least-favorite character in the series: Mahiru
I like her design and that she's a more grounded character by Danganronpa standards. The writers blew this headstart by forgetting to give her any sort of likable qualities. Her most standout personality trait is that she simultaneously puts down men and promotes toxic masculinity by telling them to 'man up', which is equally as annoying as the numerous DR characters that treat women like sex objects. I think it's telling that her best friend is Hiyoko, who is an irredeemable asshole.
None of that is even that bad by DR standards (which are not high), but what really gets me is her insane hypocrisy in Case 2. You learn that Mahiru's old friend in school killed Fuyuhiko's sister. Fuyu's sister was an asshole bully, but still, murder is bad folks. Mahiru decides to cover up the incident and try to prevent Fuyuhiko from ever finding out. Then, in Case 2, when Mahiru finds out that Fuyuhiko killed her old school friend in retaliation, she proceeds to soapbox to the guy who's emotionally compromised and freshly grieving over his DEAD SISTER, saying that he shouldn't have taken revenge because revenge is bad. Gee, I wonder why her friend gets special treatment and Fuyuhiko gets lectured? Mahiru's death is one of the only times in the series where I felt no sympathy whatsoever at a character getting offed.