Kevin Mandia’s Armadin raises $255.5M for AI agent swarms that attack your network first

Kevin Mandia built one of the best-known names in cybersecurity, then sold it to Google. Now he’s back with a startup that hacks companies on purpose. Armadin announced on October 1, 2026, that it closed a $255.5 million Series B, pushing its valuation past $2.5 billion. The pitch is simple to say and hard to build. Armadin deploys swarms of AI agents that behave like attackers, so its customers can find their weak spots before someone with worse intentions does. Who wrote the checks Andreessen Horowitz (a16z) and Accel led the heavy lifting on the round. Bain Capital Ventures and Redpoint joined as new backers. Returning investors filled out the rest of the table. That list includes Google Ventures (GV), Kleiner Perkins, Menlo Ventures, In-Q-Tel, 8VC and Ballistic Ventures. There’s a certain symmetry in GV showing up. Google bought Mandia’s previous company, Mandiant, for $5.4 billion in 2022, and now its venture arm is betting on his sequel. The Series B brings Armadin’s total funding to approximately $445 million. The company only emerged from stealth in early 2026, and its public launch in March came alongside a $189.9 million raise. What agent swarms actually do Armadin’s plat...