This study examined three Mediterranean Sea cyclones classified as medicanes: Zorbas, Ianos, and Apollo. All three cyclones traversed warm-core eddies during their propagation. We investigated the role of those eddies in the cyclones' development and the responses of those eddies to the passage of a cyclone. Cyclones Zorbas and Apollo intensified considerably in close proximity to warm-core eddies; whereas Ianos, the strongest cyclone ever recorded in the Mediterranean Sea (reaching Category 2), underwent marginal intensification. In the case of Ianos, a strong marine heatwave was present during the intensification, releasing more latent and sensible heat fluxes due to the high ocean heat content, which masked the effect of the warm core eddy. For Zorbas and Apollo, the intensification above the warm-core eddy was accompanied by moisture convergence at the warm-core eddy, yielding substantial precipitation. In the case of Ianos, the convergence of moisture and subsequent precipitation aligned with the occurrence of a marine heatwave. For Zorbas and Apollo, chlorophyll-a concentrations and Phytoplankton increased after the cyclone passed over a warm-core eddy; whereas for Ianos, they increased near the site of a marine heatwave. All three cyclones responded similarly to elevated temperatures at the mesoscale (i.e., warm-core eddy) and regional scale (i.e., marine heatwave).