From oxidative eustress and distress, to bioenergetic metabolism, and cell death, the reactive species interactome (RSI) and mitochondria are two connected metabolisms that require further investigation improving redox medicine. The step before, finding new clues needs a comprehensive discussion of the two metabolisms, and their relationship. Here, the review focuses on the RSI-mitochondria axis, from mitochondrial roles to crosstalk between mitochondria and other organelles, and the major implication of the RSI in mitochondrial roles. Specifically, the review discussed the apoptosis-necroptosis-ferroptosis death traingle, mitochondrial protein quality control system, calcium homeostasis, and mitochondrial metabolome. Through mitochondrial diseases, and mitochondrial dysfunction associated with diseases, the RSI-mitochondria axis is proposed as a brand-new perspective, including with the involvement of bacterial microbiota, on redox signaling, and redox medicine.