Armadin, the cybersecurity startup founded by former Mandiant chief executive Kevin Mandia, raised $255.5 million in a Series B round at a valuation topping $2.5 billion, according to TechCrunch and SecurityWeek.
Andreessen Horowitz and Accel co-led the round, with Bain Capital Ventures, Redpoint, 8VC, Ballistic Ventures, Google Ventures, In-Q-Tel, Kleiner Perkins and Menlo Ventures also participating, both outlets reported.
Armadin deploys swarms of specialized AI agents that act like adversaries, probing a company's attack surface, attempting exploits and chaining minor security issues into validated attack paths, according to the company. The approach already runs active campaigns for Fortune 500 and government customers, SecurityWeek reported.
"AI lets an attacker find and chain weaknesses faster than any human team can respond," Mandia said in the funding announcement, according to SecurityWeek. Mandia founded Mandiant, the incident response firm Google acquired for $5.4 billion in 2022.
The round brings Armadin's total funding to about $445 million just seven months after it launched in March 2026 with a $190 million Series A, according to TechCrunch. For builders in the security space, the signal is less about the model and more about the headcount it replaces: an agent swarm that runs a continuous red team is being sold as work a company used to hire a firm to do once a year.