A new startup led by Mandiant founder Kevin Mandia has secured a funding round from Accel and a16z to deploy autonomous security tools that simulate sophisticated adversary attacks. The Series B investment totals $255.5M and assigns the company, Armadin, a valuation of $2.5B. The company's platform uses an 'agentic attacker swarm' that reasons, plans, and adapts to help defenders identify and fix vulnerabilities across their internal networks.

The capital raise comes as chief information security officers face increased pressure to protect cloud and identity infrastructures following several cyber incidents at frontier AI labs this summer. Mandia is building the platform alongside co-founders Travis Lanham, Evan Peña, and David Slater, utilizing decades of frontline adversary tradecraft to shift how security teams handle offensive defense.