Dark Secret: An easy to miss thought of her's in 1-1 implies she has one. 2-2 reveals that as a result of being her fathers apprentice in his somewhat illegal tattoo parlor, Asuka has ties to the Yakuza.
And... I can't let him find out about...
Horrible Judge of Character: Asuka invokes this if you choose to trust Natsumi, a self-proclaimed compulsive liar who just accused you of murder, after the end of chapter two.
It's worth noting that Natsumi is actually a far more benevolent person than she might initially seem to be. This trope is still invoked with both Asuka's distrust of Natsumi during the Belladonna route, and with her trust in Yumiko, as both these opinions begin to change during Abscence.
I'm Not Here to Make Friends: Asuka maintains that she cant stand anyone else in the cast. This statement stops being true after Chapter One, when she begins explicitly referring to specific people as her friends. By Chapter Four, most of the remaining cast is her friend.
Brutal Honesty: Has no trouble saying exactly what he thinks, none of which is very nice.
Cigarette Burns: In the Belladonna route, his corpse has several of these, all over his body. It turns out later that they're not self-inflicted.
Dark Secret: Is hypersexual as the result of a childhood assault.
Jerkass: His introduction says it all, but his behaviour continues to be rotten as the story progresses.
Jerkass Has a Point: Western readers might see his criticism of Asukas tattoos to be petty, but considering how stigmatized tattoos are in Japan, its reasonable for him to be wary of her. Not to mention that Asuka actually does have Yakuza ties, so really, Itsukis suspicions of her are completely valid.
Deuteragonist: She doesn't become prominent until after the first murder, but she has an undeniable presence in the deadly life/class trial and chapter two. Following Saki's death, it becomes clear that the deuteragonist role actually belongs to Kazue.
Dark Secret: She assisted in her best friend's suicide.
Survivor's Guilt: Her first free time event reveals that she feels immense amounts of guilt about the people she's killed as a sharpshooter. Word of God confirms she also has undiagnosed PTSD.
The Atoner: Kazue feels nothing but regret for her past. She's allegedly shot nearly 500 people, and she says that she's killed more 'with [her] own hands.' She seems to be trying her best to be a good person, by caring for and defending her fellow captives.
The Stoic: Presents herself as very emotionally calm, despite the circumstances.
Turns out to be Not So Stoic in 2-2 after she has a mental breakdown. Shes really very emotional and highly affected by the deaths of everyone around her.
Super High School Level Lip Reader
Bait-and-Switch: Hes set up to be the first victim when he doesnt turn up to breakfast on the fifth morning. It isnt until the last few lines where the victim is revealed to be Kousuke instead.
Dark Secret: He's tried to kill his stepfather multiple times.
Forgetful Jones: Hes told about the potentially deadly allergies of two people and then instantly forgets about them, which leads to a massive mistake in the first trial.
In his first free time event, he reveals that he can't remember vast amounts of his childhood. Word of God has confirmed this to be trauma based amnesia.
Translator Buddy: For Ayano, as most of what she says is difficult to understand.
Unfortunate Names: The kanji in it means gathering of seafood with talent, which is not the most flattering thing to be named.
Super High School Level Volleyball Player
Break the Cutie: At the beginning of chapter one, she's incredibly perky and upbeat. The incident in the lobby causes her to have a mental breakdown, and she's much less cheerful the following morning. She goes through this again during the first class trial.
(Heavy Content Warning) And for a third time in the Ch 3 (Belladonna) trial, when she reveals that Hachirou attempted to sexually assault her.
Cool Shades: Has sunglasses that are usually held on her forehead. They fall down when shes mad.
Dark Secret: (Heavy Content Warning) She spent seven years being sexually abused by her father.
Genki Girl: Her introduction has her come off this way.
Hates Being Touched: To the point that it causes her to break down. Turns out, it's because she's a CSA victim.
Missing Mom: She's currently in foster care, and has no idea where her birth mom is.
Super High School Level Finder
Bound and Gagged: Kousuke prevents the gagging, but Minoru ends up tied up on the storage room for about 24 hours starting in 1-2.
Dark Secret: They self-harm as an outlet to severe depression.
Disappeared Dad: Left for Europe shortly after Minoru's mother died, and refuses all contact with them.
Dark Secret: She exposed someone's personal information over a grudge.
Deuteragonist: Becomes this more after Kousuke's death, when she spends more time bonding with Asuka. Unfortunately, like Kousuke, Saki is a decoy deuteragonist and ends up as the second victim.
First-Name Basis: Refers to everyone as First name-chan. The only exceptions are Yumiko, whose given name she doesnt use an honorific on at all, and Minoru, whom she refers to by their surname alone from 1-2 and onwards
The Leader: Appoints herself as such nigh immediately.
Super High School Level Linguist
Asshole Victim: Absolutely nobody is upset when he dies on the Belladonna route. Unfortunately, he becomes even more of a repulsive person to everyone else after his death. See Love Makes You Evil below.
Bilingual Bonus: Hachirou often says words or phrases in other languages to sound impressive.
Survivor's Guilt: Sakis death really pushes her into this. She outright states in chapter three that it should have been her who died.
Super High School Level Tree Climber
Dark Secret: He plays dumb and purposely gets into fights to please his athleticism obsessed parents.
Gentle Giant: Second tallest member of the cast and the strongest physically. He's also just a really nice dude. Until you find out he's the guy who knocked out Hiroki's tooth. Then it's up for debate.