<p>The military metaverse integrates immersive digital technologies, virtual worlds, artificial intelligence (AI), extended reality (XR), and digital twins to enhance capabilities across the defence enterprise. Within this framework, Digital Human Twins (DHTs) function as dynamic digital representations of military personnel and sometimes “things”, supporting training, mission planning, operational decision-making, health monitoring, equipment design and acquisition, and human–machine teaming. DHTs can be considered “actors” on a metaverse “stage”. This paper explores the role of DHTs in defence, categorising them into real human-derived, artificial, hybrid, and anthropomorphic twins, each serving one or more military functions. DHTs offer significant advantages in adaptive training, career development, operational effectiveness, and equipment optimisation, but also present challenges related to data security, AI reliability, ethical concerns, and trust in autonomous decision-support systems. To address these complexities, we propose an extended version of the Digital Twin Capability Periodic Table (CPT), originally developed for engineering digital twins, by incorporating ethical considerations, psychological fidelity, social interaction, and autonomy levels. This structured framework can support the development and governance of DHTs across defence and other domains. By adopting a comprehensive approach to DHT implementation, including interoperability, data governance, and ethical oversight, organisations can unify their human data and maximise operational benefits whilst mitigating risks. The paper concludes with strategic recommendations for implementation, emphasising research investment and trials, AI governance policies, exploiting the extended CPT, and cross-sector collaboration to refine and standardise DHT deployment.</p>