Since OpenAI fired its co-founder and Chief Executive Officer Sam Altman on Friday, a host of players across the tech industry have come onto the scene.

From co-founders to chief executives, here are their roles and how they play into the escalating series of events happening at the artificial intelligence firm.

Sam Altman

The 38-year-old American entrepreneur co-founded OpenAI in 2015 and took the reins as chief executive officer in 2019 before he was suddenly ousted by the board on Nov. 17.

Now, the company’s biggest investors, including Microsoft Corp., Thrive Capital and Tiger Global Management, are pressing the company to reinstate him.

Greg Brockman

Brockman, who co-founded OpenAI eight years ago in his apartment, quit as president on Friday hours after the board pushed out Altman. Brockman wrote in a post on the social media site X: “Based on today’s news, I quit.”

Brockman had been due to step down from his role as board chairman but stay on at the company, reporting to the new CEO.

Mira Murati

OpenAI appointed Murati as interim CEO after the company ousted Altman. She wrote that she was “honored and humbled” to take up the position, saying it was important for OpenAI to remain “focused, driven, and true to our core values,” according to a memo seen by Bloomberg.

Satya Nadella

Microsoft Corp. CEO Satya Nadella has reached out to Altman following the firing to offer him support in his next steps, people with knowledge of the situation told Bloomberg.

Microsoft is OpenAI’s largest investor with a stake worth more than $10 million. Nadella succeeded Steve Ballmer as Microsoft CEO in 2014.

Ilya Sutskever

Sutskever, OpenAI’s chief scientist and co-founder, was one of the board members who Altman clashed with over some aspects including the pace of developing generative AI, a person with direct knowledge of the matter told Bloomberg.

He asked Altman for a call on Friday and told him that he was fired on a Google Meet, Brockman said in a post on X.