Benoit Blanc returns once again in Glass Onion: A Knives Out Mystery, this time hired by Helen Brand to solve the murder of her twin sister, Cassandra "Andi" Brand. (Though viewers don't find out it's Helen until halfway through the film.) Viewers get a bit more of Blanc's home life in this movie, with his partner being played by Hugh Grant (!!) and scenes inside his apartment.

Miles Bron is a mash-up of Elon Musk, Steve Jobs, and other tech billionaires. "Miles is the furthest thing from an actual scientist," Norton explains. "Miles will be highly recognizable to anybody who's watched the WeWork documentary or the Theranos documentary. He's high on self-regard and emblematic of the self-appointed tech Illuminati. Miles Bron has never had an original idea at any phase of his life—that's a good summation of him."

In one of the twists of the film, we find out that "Andi" is actually her twin sister, Helen, who is a schoolteacher. Benoit convinces Helen to go undercover in Greece as Andi to solve her sister's murder, rightly guessing that the killer will be in attendance and thrown off by her presence.

Duke is a men's rights activist and Twitch influencer who always carries a gun on him. In the film, Duke is angling for a bigger platform, and tries to blackmail Miles with his knowledge of Andi's murder—but Miles quickly kills him with pineapple juice.

Birdie, a former model and popstar turned influencer, has her own reasons for traveling to Miles's Greek getaway. He's trying to make her take ownership over the fact her brand of sweatpants (which he gave her the seed money for) are made in a notorious sweatshop—but she knows if that comes out, it will ruin her career. She's over-reliant on her assistant, Peg, and is jealous of Whiskey's ability to get close to Miles.

Claire is Connecticut's governor who is running for Senator. Hahn didn't specify who she based her character on, but did take inspiration from high-profile female politicians. Claire's biggest ally is Lionel; they are both against him releasing Klear into the world—but Claire has staked her political career on the success of Miles and his technology.

Lionel is the head scientist at Alpha Industries; he was just a high school science teacher before he met Andi. He's definitely one of the smartest of the bunch; yet, he's just as indebted to Miles as the rest of the crew.

Whiskey is Duke's girlfriend who uses her sex appeal to try and get ahead—she sleeps with Miles to try to convince him to give Duke a bigger platform, and tells Andi (really Helen) that she wants to use Duke's platform to make a name for herself. After Duke is murdered, she becomes distraught and suspicious of everyone.

Birdie's long-suffering assistant Peg is there to make sure Birdie doesn't get into even more public mishaps—and as much as she resents her boss, she also feels very protective of her.

As Henwick shares, "This is probably someone who's tried to quit three or four times, and she can't bring herself to do it.' I thought, 'Let's make this more than just an assistant and employee relationship. It's like a toxic love/hate dynamic between the two of them.' Peg despises working for Birdie, but Birdie can't live without her. And Peg knows that. And Peg loves her. We'll go from arguing in one scene, and then the next scene we're drunk and my head is in her lap. That sums it up for me."