Elon Musk is the center of his business universe, one that includes the huge and hugely successful companies Tesla and SpaceX.

Now, Musk has added Twitter to go along with his other enterprises The Boring Company and Neuralink. The amount of work it takes to manage all of those entities seemed unfathomable even before Twitter joined Musk's constellation of companies.

Tesla is trying to grow production by 50% a year, SpaceX is trying to get to Mars, and Boring and Neuralink are doing what they do. It's a lot, and Musk has said he "works to the edge of sanity."

But for all the attention that Musk gets, he doesn't do it all alone. The best known of his lieutenants is SpaceX president Gwynne Shotwell, who speaks publicly more often than Tesla's top executives. But there are many others who can step up as Twitter demands more of Musk's time.

If anything, Musk might not get the credit he deserves for attracting top talent and building high-functioning teams. Here are a few to keep an eye on.