Rian Johnson purposely left Knives Out’s Benoit Blanc a little blank
Johnson and actor Daniel Craig were looking for a little wiggle room in the layers of their Glass Onion

Much to the occasional dismay of his audience, Rian Johnson loves to toy with viewers. But at least he plays fair: He likes toying with his actors a little too. For Glass Onion, the sequel to Johnson’s surprise hit Knives Out, the director wanted to leave things a little open-ended for the return of his lead detective, Benoit Blanc. There would be no origin story for a mustache here. Rather, he wanted to give Daniel Craig a little breathing room to make the character his own, per EW. So he “underwrote the character”
“I tried to keep any big, obvious quirks out [so] that the character would fill out with the actor,” said Johnson.
Too much focus on Blanc would no doubt back them into a corner, especially considering, as Johnson points out, the detective is rarely the main character in a mystery. “It’s a mistake of the genre to think that your detective is your main character,” said Johnson. “Benoit Blanc is the constant North Star of all of these movies. But you have to think of him as the detective, not as the central character. The story has to function in terms of the suspects, the murder, and the victim. Benoit is weaving his way through that, but the dramatic stakes are never his.”