Is the character 'Kobayashi' truly the lawyer for 'Keyser Söze', or is he an actor playing a role to assist Verbal in the performance?

Hello! That question hits the nail on the head—it cuts straight to the core of The Usual Suspects' most brilliant and enduring narrative trick.

To cut to the chase: The character Kobayashi was entirely fabricated on the spot by Verbal Kint (the real Keyser Söze) as a pawn and a lie. He was never Keyser Söze's "real" lawyer.

Let me break it down for you so it's crystal clear.

Why is "Kobayashi" Fake?

Remember the legendary, history-making twist at the end of the film?

As Verbal Kint limps out of the police station and his gait returns to normal, Detective Kujan is holding his coffee. His eyes absently scan the cluttered bulletin board in his office. Suddenly, he's struck by lightning as he starts connecting the dots between details from Verbal's story and the items on the board:

The locations in the story came from a travel poster.
The names of people came from signatures on a document.
And most crucially, the name of the lawyer "Kobayashi"—the omnipresent representative of Keyser Söze throughout the story—came from the shattered white ceramic coffee mug in Kujan's hand. The manufacturer's mark on the bottom clearly read: "Kobayashi Porcelain".

(The key scene revealing the truth in the film)

In that moment, Kujan—and the audience—realize: Verbal wasn't "recalling" events during those hours of interrogation. He was using his extraordinary powers of observation and storytelling to improvise a seamless script on the spot, weaving it entirely from the details around him.

Then Who is the "Kobayashi" We See in the Flashbacks?

This is an interesting question too. We do see a stern, imposing "Kobayashi" portrayed in the film by the late, great actor Pete Postlethwaite.

So how should we understand this "Kobayashi"?

Think of him as the visual representation of Verbal's narrated story.

Here's an analogy: If I tell you a story I made up, saying, "Yesterday I met a mysterious man named 'John Doe'. He wore a black trench coat and sunglasses and looked incredibly cool." While listening to my story, wouldn't your mind automatically conjure up a specific image of "John Doe"?

The film simply visualizes this process. Verbal is telling his story to Kujan, and the movie shows us that story through "flashback" scenes. Therefore, the "Kobayashi" we see isn't a real person existing in the film's present timeline. He is purely a fictional character—a name Verbal borrowed from the coffee cup and fleshed out with a specific image to make his lie sound more credible and intimidating.

To Summarize

Character Identity: Kobayashi is a fictional character invented by Verbal Kint (Keyser Söze) to deceive the detective, a crucial pawn in his elaborate con.
Name Origin: It came from a "Kobayashi Porcelain" coffee mug in the detective's office.
Actor's Portrayal: The actor we see in the flashbacks is playing the embodiment of Verbal's lie, not a real person. This is director Bryan Singer's masterstroke—using film to make the lie look utterly real, fooling both us and Detective Kujan.

Thus, the character Kobayashi perfectly serves the film's narrative trick. He is himself part of the myth of "Keyser Söze"—a ghost conjured into existence by the "devil" himself.

Hope this explanation gives you a deeper appreciation for this masterpiece!