AI-driven law firm Arceus Legal raises $17M to move beyond contract work

Arceus Legal has raised $17 million to push past the narrow slice of legal work that made it early traction: commercial contracts. The company says it serves fast-growing businesses with a flat price quoted before the matter begins, and that lawyers approve every piece of work with help from AI agents and software Arceus built in-house.

The pitch is speed, and the numbers are part of the sales job. A standard contract review that takes more than eight hours costs the client nothing, and Arceus says most reviews finish in three to five hours. Its website lists that service at $500. For companies watching deals get stuck while outside counsel drags the clock, that is an easy story to understand.

Arceus is also taking aim at the old habit of charging for every call and email. The company says traditional firms can take days or weeks to send back a review, and even with AI redlining tools, customers still have to verify every output themselves. Arceus says it removes that checking burden. Its attorneys work inside CounselOS, an internal system that stores client preferences, past agreements and negotiation history, then uses that context to start new matters. Salesforce, HubSpot and Gmail also feed in information from tools the client already uses, while Slack and email carry live progress updates.

So far, most of the work has been commercial contracts such as master service agreements, nondisclosure agreements and vendor deals. Some clients are already sending employment and privacy matters too, and the longer-term plan is broader than contracts: Arceus wants to become a firm that can handle all of a company’s legal needs. The company said its customer base quadrupled in September.

Greycroft LP led the round, with Craft Ventures Management, South Park Commons Management and others participating. Mark Terbeek, a partner at Greycroft, framed the bet bluntly: most legal AI startups are selling software to old firms, while Arceus is trying to rebuild the firm itself. The new money will go into hiring at Arceus’s San Francisco headquarters, with attorneys, engineers and AI researchers on the recruiting list.