The most anticipated witness in the Musk v. Altman trial finally took the stand Wednesday, and the testimony was even more complicated than the relationship itself.

Shivon Zilis, a Neuralink executive and the mother of four of Elon Musk's children, told the Oakland federal court about how she served on OpenAI's board from 2020 to 2023 while navigating what she described as an evolving relationship with one of the company's co-founders. It started, she said, with "a one-off" at a corporate off-site event. Later, when she decided to have children as a single mother, Musk "offered to make a donation" as a platonic sperm donor. Later still, it became romantic.

If you're keeping score at home: board member, co-founder's secret partner, mother of his children, and potential intelligence conduit. All the same person. All at the same time.

The Informant Question

OpenAI has argued throughout the trial that Zilis functioned as Musk's eyes and ears inside the company, funneling information to him long after he left the board in 2018. Wired previously published text messages from February 2018 in which Zilis asked Musk: "Do you prefer I stay close and friendly to keep info flowing?" She also reportedly advised Altman on how to manage Musk, positioning herself as a bridge between the feuding parties.

Zilis denied it. "I had an allegiance to the best outcome, AI for humanity," she told the court. When asked directly whether it was her job to funnel information to Musk, she rejected the characterization.

The problem with that denial is the paper trail. The text messages are real. Her continued communication with Musk about OpenAI affairs while serving on the board is documented. Whether she sees herself as an informant is one thing. Whether she functioned as one is the question the jury will have to answer.

Murati's Shadow Loomed Over Everything

Zilis's testimony came the same day the court heard from Mira Murati via video deposition. Murati's account of Altman's deceptive leadership made Zilis's role more complicated. If Altman was lying to his own CTO about safety reviews, was Zilis feeding that information to Musk? Or was she genuinely trying to keep the peace between a vindictive co-founder and a CEO she increasingly couldn't trust?

The Verge's Elizabeth Lopatto framed it perfectly: Musk's biggest loyalist became his biggest liability. The more Zilis tries to demonstrate her independence from Musk, the harder it becomes to explain why she maintained such close communication with him about a company he'd left years earlier.

What This Means for the Trial

Wednesday was arguably the most damaging day for both sides. Murati's testimony hurt Altman. Zilis's testimony, while meant to help Musk, raised as many questions about his methods as it answered. The trial runs through late May, with Altman expected to take the stand next week.

One thing is increasingly clear: whatever happens in this courtroom, the reputations of everyone involved are taking damage that no verdict can repair.

Sources: The Guardian, NBC News, NYT, The Verge, Wired, Business Insider. Zilis testified May 6, 2026 (Day 9) in Musk v. Altman, U.S. District Court, Northern District of California, Oakland.