Former Ethereum Foundation official Kayleen Fulton has filed a federal lawsuit against the organization, Ethereum co-founder Vitalik Buterin and several other defendants, alleging wrongful termination, workplace retaliation, disability discrimination and violations of medical leave protections. Fulton, known in the Ethereum community as Nixo, filed her complaint on November 4, 2026, in the U.S. District Court for the District of Colorado. The case, numbered 1:26-cv-05818, challenges her dismissal on April 6 following an internal dispute over the foundation’s revised organizational mandate.The defendants include Switzerland-based Stiftung Ethereum, Singapore affiliate Ethereum Asia Pacific Limited, executive Bastian Aue, Buterin and two employment-service companies. Fulton, who previously led the foundation’s Protocol Support team and facilitated Ethereum’s All Core Developers meetings, is seeking lost wages, compensatory and punitive damages, and other legal relief. The allegations have not been adjudicated, and no court has determined that the defendants violated employment laws.
Dispute Over Ethereum Foundation Mandate Preceded Dismissal
The lawsuit centers on the Ethereum Foundation Mandate, an organizational document published on March 13 that defined the foundation’s mission around censorship resistance, open-source development, privacy and security. The document included a controversial provision called the Source Seppuku License, containing language referring to contributors taking their own lives with a sword if they failed to uphold its commitments. Foundation management clarified that the language was symbolic rather than a literal instruction. Nevertheless, according to the complaint, 79 employees voted to remove the provision during internal discussions.Fulton and colleague Trent Van Epps subsequently organized a March 25 letter signed by 53 members of the foundation’s protocol-related teams. The letter supported the organization’s broader strategic direction but opposed what its signatories considered coercive conditions requiring employees to affirm the mandate or leave. Both organizers were dismissed on April 6, according to the filing. Fulton alleges their dismissals constituted retaliation for organizing collective employee opposition. She separately claims that the foundation terminated her less than two weeks after she disclosed an ovarian cancer diagnosis on March 24. The complaint alleges that management failed to provide appropriate medical leave information or consider accommodations before ending her employment.
Buterin Named in Lawsuit as Former Employee Challenges Separation Agreement
Fulton’s lawsuit also cites a May 1 conversation with Buterin in Norway, which she says she partially recorded. According to the complaint, Buterin discussed concerns that rewarding employees for publicly challenging management could encourage similar disputes over organizational decisions. Fulton’s lawyers argue that the remarks support her retaliation allegations. However, the filing does not establish that Buterin personally ordered her dismissal. The lawsuit also challenges a separation agreement Fulton says she signed under pressure after being given a limited period to accept its terms. She is seeking to invalidate the agreement, including provisions requiring certain disputes to undergo arbitration in Singapore.The complaint invokes federal protections under the Family and Medical Leave Act and disability discrimination provisions, alongside Colorado employment laws. Fulton previously filed a discrimination charge with the Equal Employment Opportunity Commission and received a notice permitting her to pursue litigation in September. The Ethereum Foundation and Fulton had not responded to The Block’s requests for comment before its November 9 report. The lawsuit introduces legal scrutiny of the foundation’s internal governance during a period of organizational restructuring. Its outcome will depend on evidence concerning the reasons for Fulton’s dismissal, the defendants’ individual responsibilities and the enforceability of her separation agreement.