As Elon Musk puts the finishing touches on his $44 billion dollar deal to buy Twitter, the world’s richest man continues to consult with a coterie of loyal confidants, investors, board members and researchers who are part of his inner circle.

They include young scientists who head up research into Artificial Intelligence at companies such as Tesla Motors and Neuralink, a brain-implanted startup he controls. There are also longtime investors, a celebrity lawyer and Musk’s younger brother — all of them unflinching when it comes to Musk’s mercurial approach to business and innovation.

“When Elon says something, you have to pause and not blurt out ‘Well, that’s impossible,'” said Gwynne Shotwell, an engineer and head of Musk’s space exploration company, SpaceX, at a 2018 TED conference in Vancouver. “You zip it, you think about it, and you find ways to get it done. I’ve always felt like my job was to take these ideas and turn them into company goals, to make them achievable.”

Here are some of Musk’s closest confidants:

One of Musk’s most trusted confidants and his personal fixer, Birchall is the CEO of Neuralink, a neurotechnology company co-founded by Musk in 2016 with the aim of connecting humans to computers by inserting a chip in the brain. The 47-year-old is also the managing director of Excession LLC, the so-called Musk family office that manages his net worth of more than $264 billion.

In 2018, when Musk faced a defamation suit from British rescue diver Vernon Unsworth after calling him “a pedo guy” on Twitter, Birchall tried to help his boss by hiring a private investigator to dig up information on Unsworth, who was involved in the rescue of a group of young Thai soccer players trapped in a cave. But after Musk sent some of the details to a reporter, the private investigator was revealed to be a convicted felon peddling false information.

Birchall is a former financial advisor at Goldman Sachs and senior vice-president at Morgan Stanley. He has homes in Texas and California, and is treasurer of the Musk Foundation, an Austin-based non-profit that has doled out tens of millions of dollars to education, pediatric and environmental research, among other causes.

He has no Twitter presence.

Forbes named the engineer — who is chief operating officer and president of SpaceX — the 38th most important woman in the world in 2021. Shotwell, 58, who grew up in the Chicago suburbs, was the 11th employee of SpaceX, and joined the company in 2002, the same year Musk formed the space exploration firm. She is fiercely loyal to Musk, according to reports.

Shortly after she was hired, Shotwell organized a meeting with government customers for a potential satellite launch, according to author Eric Berger in his 2021 book “Liftoff: Elon Musk and the Desperate Early Days That Launched SpaceX.”

“They were going to be there in an hour, and it was a mess,” Shotwell told the author. “So I got out the vacuum. The vice president of sales vacuuming and then trying to figure out coffee.”

She has 23,400 followers on Twitter.

Musk’s personal attorney was born in New York City and raised in Boston, and worked as a former prosecutor at the Manhattan District Attorney’s Office until 2013. He prosecuted Rodney Alcala, the “Dating Game Killer” in 2012. The Brooklyn-based lawyer, who has worked with musicians Mick Jagger and Jay-Z, among other celebrities and sports personalities, successfully represented Musk in the defamation case brought against him by British cave diver Vernon Unsworth in 2018.

Spiro, 39, has no Twitter profile.

Musk’s younger brother, 49, sits on the boards Tesla Inc. and SpaceX. A Colorado-based philanthropist and food entrepreneur, he is the co-founder of Square Roots, a Brooklyn-based hydroponic urban farm that aims to reduce waste by growing vegetables in old shipping containers. He is also co-founder of Big Green, a non-profit that has built hundreds of outdoor classrooms called “Learning Gardens” in schoolyards across the US.

He’s also rarely seen without a cowboy hat.

A registered Democrat, he gave a total of $5,600 to Friends of Schumer to support US Senator Chuck Schumer in New York in 2021, according to public records. He also contributed a total of $19,600 to WinRed in 2021, according to the Federal Election Commission. The political action committee supports Republican candidates.

Kimbal Musk has 259, 700 followers on Twitter.

The Chicago-based financier is a longtime Musk friend and confidant. He’s the founder of Valor Equity Partners and met Musk through law school friends at the University of Chicago in the 1990s — and has been an early investor in Musk’s companies.

Gracias, 51, began investing in Tesla in 2005, two years after the launch of the company. He joined its board in 2007. Until last year, he was the Lead Independent Director at Tesla Motors when his term on the board expired.

Born in Detroit, and raised in Grand Rapids, Gracias is the son of Indian and Spanish immigrants. He is on the board of SpaceX and has guided Musk’s purchase of $1.5 billion worth of bitcoin in 2021, according to a report. Gracias was a big supporter of Rahm Emmanuel, the former mayor of Chicago who is now US Ambassador to Japan. Last year, he doled out a total of $5,000 to Mark Kelly, a US Senator representing Arizona and a former astronaut.

Gracias has no presence on Twitter.

Zilis, 36, is director of operations and special projects at Neuralink and OpenAI, a Musk company that researches artificial intelligence for “the benefits of all humanity,” according to her LinkedIn profile. The Yale graduate works on “high-priority strategic initiatives” in Musk’s office at Neuralink, and is the youngest board member on OpenAI’s board of directors.

Two years ago she tweeted support for her boss in response to online criticisms. “This makes me very sad,” Zilis tweeted in response to a Twitter user who posted “F–k Elon Musk” “No one’s perfect. But I’ve never met anyone who goes through more personal pain to fight for an inspiring future for humanity — and has done so tirelessly for decades. Everyone’s entitled to their opinion but mine is that there is no one I respect and admire more.”

Zilis has 68,600 Twitter followers.

Karpathy is senior director of AI at Tesla, a position he has held for the past five years. A former Google intern, the 35-year-old was one of the founding members of OpenAI before Musk put him in charge of AI at Tesla Motors. According to the New York Times, a few months after founding OpenAI, Musk deployed researchers like Karpathy to help with Tesla’s assisted driving system.

“Andrej is really one of the best computer vision people in the world, arguably the best,” said Musk in a 2021 video on how Tesla uses AI to power their self-driving cars.

Karpathy was born in Slovakia and moved to Toronto when he was 15. He completed a PhD at Stanford in 2015 under the direction of Fei Fei Li, a computer scientist and Stanford professor who is a current member of the Twitter board of directors.

Karpathy has 476,300 followers on Twitter.