Animal carcasses represent localized nutrient pulses that can influence soil microbial communities and biogeochemical processes, particularly in nutrient-depleted soils. However, how biotic factors (e.g., scavenger activity, carcass type and vegetation cover) shape these belowground effects remains poorly understood. Here, we experimentally assessed changes in soil microbial community structure and activity following carrion decomposition and their modulation by these biotic drivers in a Mediterranean dryland. We deployed 10 red fox (Vulpes vulpes) and 10 aoudad (Ammotragus lervia) carcasses in Sierra Espuna Regional Park (Murcia, Spain) and measured soil microbial community composition (phospholipid fatty acid profiles), activity (basal respiration, microbial biomass carbon and extracellular enzymatic activities) and physicochemical properties before deployment and five months later. Scavenger activity was assessed with camera traps and vegetation cover was recorded for each carcass. Carrion deposition significantly altered soil conditions, decreasing pH (-2.5%) and increasing electrical conductivity (+82.2%) and phosphorus availability (+449.7%). Microbial communities shifted markedly, with Gram-negative bacteria increasing importantly (+246.7%) and Gram-positive groups declining (-28.6%), while total microbial biomass and activity showed limited changes. These responses were strongly modulated by biotic factors: carcasses consumed by more scavenger species showed dampened microbial responses, whereas denser vegetation cover enhanced microbial responses. Carcass type also modulated microbial responses, with mesocarnivore carcasses inducing stronger shifts relative to their mass, likely due to longer persistence and differential scavenging dynamics. Our findings demonstrate that carrion effects on soils depend not only on nutrient inputs but also on large-scale ecological processes regulating carcass persistence. By linking scavenger activity and vegetation structure with microbial responses, our results highlight carrion as a key interface coupling above- and belowground processes, ultimately shaping microbial heterogeneity and regulating zoogeochemical nutrient pathways in dryland ecosystems.