The regulation of military applications of artificial intelligence (AI) is a growing concern. The article investigates how the EU as a multi-level system aims at regulating military AI based on epistemic authority. It suggests that the EU acts as a rule-maker and a rule-taker of military AI predicated on constructing private, corporate actors as experts. As a rule-maker, the EU has set up expert panels such as the Global Tech Panel to inform its initiatives, thereby inviting corporate actors to become part of its decision-making process through the front-door. But the EU is also a rule-taker in that its approach to regulating on military AI is shaped through the backdoor by how corporate actors design AI technologies. These observations signal an emerging hybrid regulatory security state based on 'liquid' forms of epistemic authority that empowers corporate actors but also denotes a complex mix of formal political and informal expert authority.