Fulton sues Ethereum Foundation and Buterin over April firing

Kayleen Fulton, the former head of the Ethereum Foundation's Protocol Support team, filed a federal complaint against the foundation, co-executive director Bastian Aue and co-founder Vitalik Buterin on November 4, 2026 in the U.S. District Court for the District of Colorado. The complaint seeks damages for disability discrimination, medical-leave interference and retaliation after Fulton — who goes by "Nixo" in the community — was terminated on April 6, 2026, thirteen days after disclosing an ovarian cancer diagnosis.

The primary document is the complaint PDF on CourtListener (docket 1:26-cv-261399). Main secondary coverage: The Block and Protos.

What happened

The complaint names six defendants: the Ethereum Foundation (Stiftung Ethereum, Zug), its Singapore affiliate Ethereum Asia Pacific Limited, the foundation's U.S. employer-of-record Lightsource HR Global, payroll processor Vensure Employer Services, Aue and Buterin. Per Unchained's count, it brings eleven claims; Buterin is named in five of them. The claims include disability discrimination and retaliation under federal and Colorado law, FMLA interference and retaliation, and a Colorado aiding-and-abetting count against Aue and Buterin personally.

Fulton led the foundation's Protocol Support team and ran the All Core Developers call rotation — the same team the foundation dissolved on July 9, roughly three months after her firing.

The "Source Seppuku License"

The dispute turns on a clause of the EF Mandate, an internal commitment document published March 13, 2026. The section is titled "Source Seppuku License" and invokes a suicide pledge for failing to uphold an obligation to Ethereum. The complaint quotes management as having rejected a literal reading of the clause, but describes the language as a trigger for dissent among protocol staff.

Per the filing and corroborating reporting:

• March 19, 2026: Fulton receives an ovarian cancer diagnosis.
• March 24: Fulton discloses the diagnosis in writing to EF leadership.
• March 25: A letter signed by 53 members of the protocol team — coordinated with Trent Van Epps — is sent to leadership asking that the "Seppuku License" clause be withdrawn.
• April 6: Fulton and Van Epps are terminated approximately thirty minutes apart.
• May 1: Fulton partially records a private conversation with Buterin in Norway. The complaint quotes Buterin as saying that "if you reward making a stink with outcomes," employees would use the pattern to push foundation decisions.

Relief sought

Fulton seeks back pay, compensatory and punitive damages, reinstatement or front pay, and a declaratory judgment voiding her separation agreement. The agreement — which Fulton says she signed under duress before rescinding — offered one year's salary; the foundation revoked the offer on April 17, per the complaint. The filing also asks the court to find the agreement's Singapore-seat arbitration clause unenforceable.

Attribution and pattern

These are allegations in a civil complaint and remain unproven. The Block reports it reached out to Fulton and the Ethereum Foundation and had not received a response at publication.

The suit is the third major governance event at the foundation this year, after the June 23 restructure that cut 54 positions and 40% of the 2026 budget and the July 9 dissolution of Protocol Support. The Mandate document that anchors the complaint was the public commitment the June restructure rested on; litigation now puts the Mandate itself — and personal liability for its principal signatories — in front of a U.S. federal court.

What to watch

1. Answer and motion to dismiss: EF's response and any Rule 12(b) motion challenging jurisdiction over the Zug and Singapore entities.
2. Arbitration clause ruling: whether the Colorado court sends Fulton's claims to Singapore arbitration or keeps them in Denver.
3. Discovery: the May 1 recording's admissibility in Norway (one-party-consent rules differ by state).
4. Related suit: whether Van Epps, the other terminated organizer, files his own complaint.