This article examines the evolving nature of antagonistic threats in the context of intelligence and security services, with a focus on small and medium-sized countries. It explores the impact of hybrid threats and non-linear warfare in an increasingly blurred security landscape between war and peace. The study aims to understand the emerging dynamics of the grey zone and the new challenges these evolving threats pose to intelligence and security services. The article adopts a qualitative methodology, drawing on global examples and including the strategic use of hybrid warfare by both state and non-state actors. In addition, the study examines technological advancements, particularly in artificial intelligence (AI) and machine learning (ML), to assess their role in shaping modern threats. The article argues that modern antagonistic threats differ from traditional ones in both intensity and complexity. Hybrid threats operate across multiple domains, blending military and non-military tactics while exploiting societal vulnerabilities. The article highlights the growing importance of AI and ML in both offensive and defensive strategies as well as the challenges posed by rapid technological advancements beyond state control. The article concludes that intelligence and security services must adapt to these multi-dimensional threats by embracing flexible integrated strategies. Enhanced international collaboration, advanced technological integration, and a focus on resilience will be the key to countering hybrid threats. The findings underscore the need for intelligence services to operate beyond traditional boundaries to effectively manage the complexities of future security environments.