Armadin, founded by Kevin Mandia, raised $255.5 million in a Series B led by Andreessen Horowitz and Accel, pushing its valuation past $2.5 billion. Bain Capital Ventures and Redpoint joined as new backers, while Google Ventures, Kleiner Perkins, Menlo Ventures, In-Q-Tel, 8VC and Ballistic Ventures returned. The round brings Armadin’s total funding to approximately $445 million. The company uses swarms of specialized AI agents in sandboxed environments to simulate attacks on replicated systems, helping enterprises and government agencies identify vulnerabilities before real attackers exploit them. Armadin plans to use the proceeds for platform expansion, research and model training, and sales and go-to-market development. Mandia previously founded Mandiant, which Google acquired for $5.4 billion in 2022.