A good murder mystery needs a killer at the core of it. A hole to fill a donut, if Benoit Blanc's particular phraseology fits the bill. For Glass Onion: A Knives Out Mystery, the sequel to his phenomenally successful Knives Out, director Rian Johnson pinpointed his latest killer as a tech mogul with a gigantic ego - and that meant, as a result, the entire film had to be bigger in scale and gloss.

Miles Bron (Edward Norton), the inventor of 'Klear', a hydrogen-based alternative fuel, invites his circle of friends to his private island after finally ridding himself of Andi Brand (Janelle Monáe) - only to be stunned when Andi turns up. Or so he thinks, as it's actually her twin sister Helen, disguised as Andi, who appears to assist Benoit Blanc (Daniel Craig) in uncovering the truth.

When deciding why Miles would be the killer — after all, this is a man who invited friends to a murder mystery weekend a week after committing a murder — Johnson explained that he wanted it to be a colossal idiot, a man who believed his own hype and therefore could get away with it, before ultimately being brought down by his own lack of intelligence.

RELATED: Rian Johnson Talks 'Glass Onion: A Knives Out Mystery,' How He Came Up With the Plot, and ‘Knives Out 3’

Speaking to Empire via their Spoiler Special podcast on the movie, Johnson expanded on this, admitting he settled on the idea of Miles being the center of the puzzle from the very beginning.

It was very, very early. It was always the idea behind it, that’s where I came up with the notion of the glass onion. I wanted a big, dumb, obvious lie and it being made possible by the complicity of people who had a vested interest in that lie - and how big and obvious can you make it, under the guise of someone trying to play 3D chess with you? That more than anything is what the movie is about, so we need a character like Miles. The movie is an angry movie, there’s a lot of howling at the stupidity of what we’ve gone through in recent years with public figures, so we needed a larger-than-life central figure. If anything, I feel like Miles is underplayed compared to real life.

Glass Onion: A Knives Out Mystery is currently streaming on Netflix. You can see our interview with Johnson down below.