Leader, Josh and Larry.

The leader is literally a white square.
He has a very simple rectangular/square silhouette, white in color, with no hair, clothing, or stubble. His face is composed of minimalist, cartoonish features. He looks extremely geometric and simple—basically, a "white square with a face." It's his shape that most distinguishes him from the others.
Larry is a white character with glasses.
He has no hair or clothing. His main distinguishing feature is his glasses, which immediately distinguish him from the trio. His build and overall design remain very simple, flat, and cartoonish.
Josh is a white character with stubble.
Like the others, he is hairless and naked. His most distinctive feature is the dark stubble on his face. It stands out against his white face and makes him visually distinguishable from the Leader and Larry.

The leader is the cocky, hot-tempered, and rather dramatic ringleader of the trio. He views himself as the true leader and speaks for all three. However, he easily loses his temper, especially when he feels they aren't being taken seriously. He's proud of his people's past and talks about how they were once stripped of power and exiled. His "villainy" is quite comedic: he's not some cold genius, but rather a resentful, embittered, and overly self-assured man who believes the world is owed recognition. In conversation, he can literally veer from pompous speech to a completely mundane argument with Larry and Josh.
Larry is calmer and more down-to-earth, but still just as absurd as the others. He's often the one trying to justify or explain his actions. For example, when the Leader accuses him of ruining their "chick magnet," Larry defends himself and reminds them that no one criticized him while everyone else was enjoying the results of his work. So he's not just a silent subordinate: he has his own opinions and is perfectly capable of arguing with the Leader. At the same time, he remains part of their shared, completely absurd worldview.
Josh is the calmest, most unflappable, and most unemotional of the three. Unlike the Leader, he rarely tries to dominate the conversation and doesn't seem like someone who constantly wants to prove something. His reactions are usually very restrained, and his manner of speaking is dry and calm.

The Leader is the most dominant and assertive of the trio. He's used to speaking for all three and perceiving himself as the leader. However, he's easily irritated and reacts emotionally when he feels they're underestimated or not taken seriously. He has a strong sense of being unfairly forgotten. He tells Kiki that their ancestors were once powerful beings in the universe, after which they were stripped of their power and exiled. Now the trio live in exile and consider themselves "discarded" by society. But his main modern dream isn't conquering the universe. When Kiki suggests they want to rule the world again, the Leader bluntly denies it. They want girls and attention from women. That's why they've been working for years on a chick magnet—a machine that should make them attractive to women. Behind his aggressiveness and pathos lies a rather simple desire: to stop feeling rejected and unwanted.
Larry is the more talkative and down-to-earth member of the trio. He's capable of debating with the Leader and defending himself, rather than simply mindlessly following his orders. A particularly telling moment is the story of their "chicken magnet." The Leader accuses Larry of ruining everything, and Larry calmly reminds him that he himself benefits from his work—eggs—every day. So Larry has his own opinions and a sense of justice, even if he remains part of a completely absurd scheme. He's also involved in their overall plan: they want to get their hands on Saira's lab axe, because it's supposed to be the power source for their new chick magnet. To achieve this, they kidnap Kiki and use her as bait. Larry, however, doesn't seem like someone with any grand ambitions for power. His desires are roughly the same as the others: attention, romantic/female recognition, and a sense of self-importance.

Josh is the most unflappable and emotionless of the three. He's far less likely to be the type to constantly prove himself right. In conversations, he often remains in the background, responding briefly and calmly, sometimes simply mumbling incoherently. And that's precisely why he's funny: utter idiocy can be unfolding around him, the Leader can be indignant, Larry can argue—and Josh remains almost as calm. Yet he's not isolated from the others; he's still part of their larger plan and their little group. They live together in exile in their man cave and have been trying for years to create/obtain a chick magnet. Josh isn't shown to have a separate, larger dream distinct from the others. Canon rather presents them as three lonely men united by a shared dissatisfaction with their lives and a desire for female attention. The creators directly called them "incels of the future" and noted a parallel between them and Saira: both believe that happiness will come if they manage to get a specific person. They live in exile in their man cave—a kind of male refuge on the fringes of society. Once powerful, their people now consider themselves forgotten and marginalized. Their home reflects their state quite well: it's not a majestic villain's palace, but rather three men holed up together in their cave, trying to figure out how to finally become attractive to women.