This study investigates the microbial dynamics during the decomposition of terrestrial human cadavers across three locations with different climates. The researchers tracked 36 human cadavers over 21 days to understand how microbial communities assemble and function during decomposition, despite variations in location, climate, and season. They used multi-omics data, including 16S and 18S ribosomal RNA gene amplicons, metagenomics, and metabolomics, to analyze the microbial responses. Key findings include: 1. **Consistent Microbial Network**: A universal microbial decomposer network assembles, characterized by cross-feeding to metabolize labile decomposition products. This network is phylogenetically unique and rare in non-decomposition environments. 2. **Environmental Influences**: The assembly of the microbial decomposer community is influenced by environmental conditions, with temperate climates showing more pronounced microbial responses compared to semi-arid climates. 3. **Key Microbial Decomposers**: Specific bacterial and fungal decomposers, such as *Oblimonas alkaliphila* and *Yarrowia*, are identified as key players in the network. These decomposers are found in various animal remains, suggesting their generalizability across different types of carrion. 4. **Cross-Feeding and Resource Partitioning**: The network exhibits increased cross-feeding potential from early to advanced decomposition stages, indicating metabolic efficiency and resource utilization. 5. **Machine Learning for Forensic Applications**: The study demonstrates the potential of using microbial community succession patterns and machine learning to predict the postmortem interval (PMI) accurately. The models are robust and can predict PMI within ~3 calendar days, making them useful for forensic investigations. 6. **Implications for Ecosystem Ecology**: Understanding the microbial ecology of decomposing cadavers provides insights into carbon and nutrient budgets, contributing to better models of ecosystem function and change. Overall, the study reveals a conserved interdomain microbial network that underpins cadaver decomposition, with implications for forensic science and ecosystem ecology.This study investigates the microbial dynamics during the decomposition of terrestrial human cadavers across three locations with different climates. The researchers tracked 36 human cadavers over 21 days to understand how microbial communities assemble and function during decomposition, despite variations in location, climate, and season. They used multi-omics data, including 16S and 18S ribosomal RNA gene amplicons, metagenomics, and metabolomics, to analyze the microbial responses. Key findings include: 1. **Consistent Microbial Network**: A universal microbial decomposer network assembles, characterized by cross-feeding to metabolize labile decomposition products. This network is phylogenetically unique and rare in non-decomposition environments. 2. **Environmental Influences**: The assembly of the microbial decomposer community is influenced by environmental conditions, with temperate climates showing more pronounced microbial responses compared to semi-arid climates. 3. **Key Microbial Decomposers**: Specific bacterial and fungal decomposers, such as *Oblimonas alkaliphila* and *Yarrowia*, are identified as key players in the network. These decomposers are found in various animal remains, suggesting their generalizability across different types of carrion. 4. **Cross-Feeding and Resource Partitioning**: The network exhibits increased cross-feeding potential from early to advanced decomposition stages, indicating metabolic efficiency and resource utilization. 5. **Machine Learning for Forensic Applications**: The study demonstrates the potential of using microbial community succession patterns and machine learning to predict the postmortem interval (PMI) accurately. The models are robust and can predict PMI within ~3 calendar days, making them useful for forensic investigations. 6. **Implications for Ecosystem Ecology**: Understanding the microbial ecology of decomposing cadavers provides insights into carbon and nutrient budgets, contributing to better models of ecosystem function and change. Overall, the study reveals a conserved interdomain microbial network that underpins cadaver decomposition, with implications for forensic science and ecosystem ecology.