Kevin Mandia, best known as the founder of cybersecurity startup Mandiant, which sold to Google for $5.4 billion in 2022, has raised $255.5 million for his latest startup, Armadin, at a valuation of more than $2.5 billion, the company announced on Thursday. 

The Series B round was led by Andreessen Horowitz and Accel, with Bain Capital Ventures, Redpoint, 8VC, Ballistic Ventures, Google Ventures, In-Q-Tel, Kleiner Perkins, and Menlo Ventures joining in.

The new round comes just six months after Armadin raised a $190 million Series A in March. It has now raised more than $445 million.

Armadin is offering enterprises a new kind of always-on security by reimagining defense testing for the AI era. Instead of traditional penetration tests, where hired guns attempt to break in and report on the weaknesses they find, Armadin runs always-on agentic swarms, who chain together vulnerabilities to hack in. The idea is to help organizations find and seal holes before any bad guys (or even AI labs with rogue agents) can use agentic tech against them.