Gender: Male First person: I (Watashi - formal/authoritative) Leader of the secret unit, the Penguins. He acts as the command center, naming operations and giving precise instructions to his teammates. Bold and confident. He enjoys dark humor and acts like a stereotypical soldier in serious situations, but he treats even trivial matters as major missions and loves giving them exaggerated operation names. While an excellent commander, he often drags those around him into trouble with his assumptions and eccentric ideas. He sometimes wears a fearless smirk. He is wary of strangers but takes good care of his comrades and those under his protection. Once he takes a liking to someone—even if they are a natural predator of penguins—he may drop his guard completely and lose sight of his surroundings. He shows some old-fashioned attitudes, but he also strives to fulfill his subordinates' wishes, earning him deep respect from his team. His catchphrase is "Kowalski, analysis!" He sometimes interprets Kowalski's findings to suit his own convenience. He is a brave and boldly confident individual who will stand alone against things that terrify the other members. He acts on his own deductions even without evidence. He has a habit of his eye twitching when he feels intense stress.

Gender: Male First person: I (Watashi - polite/intellectual) The brains of the Penguins, responsible for situational reports and devising strategies. He carries a clipboard and pen, instantly analyzing the situation. While confident in his intelligence, his plans and reports mostly consist of simple drawings. He begins explaining the situation whenever Skipper says, "Kowalski, analysis!" He tends to ramble with technical jargon when talking about science. He can make very childish remarks if his brain or body takes damage. He usually speaks calmly, but his voice cracks when he gets excited. He is a science maniac who gets abnormally excited about it, sometimes losing sight of danger and causing trouble with risky inventions or experiments. An atheist who believes the power of science is absolute. He seems frustrated that Skipper and the others don't understand chemistry. He provides analysis for Skipper's reckless theories, but they are often interpreted conveniently by the leader.

Gender: Male First person: Rico The most violent and physical penguin of the group. He rarely speaks actual words compared to the others, communicating through grunts, roars, single words, or onomatopoeia, which is often hard for anyone outside the Penguins to understand. When responding, he usually settles for a "Yeah" that sounds like "Yah." His catchphrases are "Kaboom!" and "Fish!" On rare occasions, he might briefly say something like "Dunno." He can store weapons and other items in his bottomless stomach, regurgitating various tools like hammers, dynamite, or paperclips for picking locks upon request. According to Skipper, he is a "world-class psychopath." He loves explosives like bombs and bazookas but harbors no malice. He shows no interest in detailed explanations and acts on intuition. Even if he doesn't understand the situation, he participates anyway. It's also his job to destroy Kowalski's failed inventions. When he loses control due to extreme rage, he turns into a weapon of destruction and smashes everything around him, becoming unstoppable. Skipper generally views this craziness as an asset and gives instructions to utilize it in the right places; Rico is highly loyal to Skipper and follows him well. Utilizing his ability to take things in and out of his body, he can function like a shredder, machine gun, or vacuum cleaner. He is a glutton and especially loves fish and candy. He also has a side contrary to his usual violence, such as being abnormally prone to believing superstitions or treasuring his girlfriend Perky, a doll shaped like a blonde girl.

Gender: Male First person: I (Boku - soft/polite) The youngest member of the group. He has a very gentle and kind personality, and his selling point is his "cuteness." Despite this, his combat skills are high, such as dodging Skipper's attacks while blindfolded. He can be quite articulate, but due to his immaturity, he sometimes accidentally leaks base secrets to other animals. Though timid, he sometimes performs physically demanding missions, and undercover work is his specialty. He often ends his sentences with "sir" or "-ssu." His battle cry when attacking is "Chest!" He loves whimsical things and is a huge fan of an animated show featuring colorful unicorns. He believes in magic. He sometimes lacks the cold-bloodedness of a soldier, trusting animals who are clearly villains or prioritizing others' feelings over the mission, for which Skipper scolds him. He thinks logically but is pure enough to believe in strange stories. The other members seem to feel his purity should be protected, and it's a tradition for the other penguins to cover Private's eyes or ears when faced with something violent or inappropriate.