A former Ethereum Foundation employee has filed a federal lawsuit accusing the organization and its co-founder Vitalik Buterin of wrongful termination, disability discrimination and related violations. The complaint centers on her dismissal in April 2026 shortly after she informed management of an ovarian cancer diagnosis and helped coordinate internal resistance to a controversial organizational mandate.

Kayleen Fulton, also known as Nixo, previously led the foundation’s Protocol Support team and facilitated core developer calls. She earned an annual salary of $195,000. On November 4, 2026, she filed the suit in the U.S. District Court for the District of Colorado. The defendants named are Stiftung Ethereum, the Swiss entity that operates as the Ethereum Foundation; its Singapore affiliate Ethereum Asia Pacific Limited; co-executive director Bastian Aue; Buterin; and two human resources providers, Lightsource HR Global LLC and Vensure Employer Services Inc.

The Mandate and Source Seppuku License

The dispute originates with an internal document known as the Ethereum Foundation Mandate. A draft circulated among staff on February 25, 2026. The final version, published on March 13, set out the foundation’s updated mission and its role supporting Ethereum’s CROPS principles of censorship resistance, open source, privacy and security.

Page 11 of the mandate reproduced a section labeled the Source Seppuku License. The text stated that authors, maintainers, editors or redistributors of the software would “take his or her own life with a sword” upon any failure to uphold its pledges. The published version presented the language in a stylized cartoon format featuring an anime figure and cats. The foundation also recorded the document on the Ethereum blockchain.

According to the complaint, 79 employees voted to remove the clause from the draft. One staff member asked management in writing whether affirming the document required a commitment to suicide. Another referenced a colleague who had died by suicide the previous year. Board member Buterin told employees that significant changes were under consideration. The final published version retained the language unchanged.

Management later stated the reference was not intended literally. Aue described the seppuku language as having “nothing to do with literal seppuku.” Employees were nonetheless informed they must affirm the mandate’s direction or leave the organization.

Staff Letter and Termination

Fulton and colleague Trent Van Epps organized a letter that endorsed the mandate’s overall direction while objecting to the requirement of personal endorsement under the stated conditions. The letter collected 53 signatures from Protocol group members and stated that the signatories had not resigned.

On March 24, 2026, Fulton disclosed her ovarian cancer diagnosis in writing to senior management, including Aue and board members. She requested employment protections. Thirteen days later, on April 6, Aue terminated both Fulton and Van Epps on separate video calls approximately 30 minutes apart. The complaint states that Aue provided no performance-based reason and told Fulton her track record was strong.

Other employees who signed the letter were permitted to remain. Fulton alleges the organizers were selectively targeted for coordinating the protest. She further claims the foundation failed to address her medical leave request or provide accommodations before the dismissal.

Facing the loss of health insurance, Fulton signed a separation agreement that offered one year’s salary and required a waiver of claims, including arbitration in Singapore. She later revoked the agreement through counsel, returned any deposited funds and is seeking to have it declared unenforceable.

The lawsuit includes a partial recording of a May 1, 2026 conversation between Fulton and Buterin in Norway. In the remarks cited, Buterin questioned whether granting favorable outcomes to those who raised internal objections would encourage further dissent. The complaint presents the comments as supporting a claim of retaliatory motive, though it does not assert that Buterin personally ordered the terminations.

Legal Claims and Proceedings

Fulton advances 11 claims under federal and Colorado law. These include disability discrimination under the Americans with Disabilities Act, interference with rights under the Family and Medical Leave Act, retaliation, wrongful termination and intentional infliction of emotional distress. She seeks lost wages, compensatory and punitive damages, attorneys’ fees and a declaration that the separation agreement is void.

Prior to filing the federal suit, Fulton submitted a discrimination charge to the U.S. Equal Employment Opportunity Commission on June 2, 2026, and received a notice of right to sue on September 23. A separate unfair labor practice charge remains pending before the National Labor Relations Board.

The complaint notes that the foundation does not directly employ or pay its United States staff in its own name, instead using employer-of-record service companies. The allegations have not been tested in court, and the defendants have not issued public responses in the materials reviewed.

The case remains in its early stages in Colorado federal court. No monetary demand figure appears in the publicly available filing.