Massive stars have far-reaching feedback effects that alter the surrounding environment on local, global, and cosmic scales. Spectral analyses of massive stars with adequate stellar-atmosphere models are important to study massive star feedback in detail. We discuss the most recent UV and optical studies of massive metal-poor stars, including those with metallicities ranging from half to one twentieth of solar, connected with large-scale ISM structures in the Magellanic Clouds and the tidal Magellanic Bridge. We present ionizing fluxes from massive stars with low metallicity along with mechanical energy, and we further compare these to the observed energetics in the ISM. The results give hints on the leakage of hot gas and ionizing photons in the Magellanic Clouds. The paper outlines feedback from individual massive stars to population-level collective feedback, the significance of various feedback mechanisms (radiation, wind, supernova), and the influence by the physical conditions of the ISM