Tumor heterogeneity hampers the clinical efficacy of cancer chemotherapy. Therefore, it is necessary to develop a multifaceted, rational treatment strategy with the potential to modulate overall tumor heterogeneity. Since combination therapy using several drugs has been shown to have enhanced therapeutic effects compared with monotherapy, combining agents with different antitumor effects would be a multifaceted form of therapy to overcome tumor heterogeneity. Therefore, the development of effective drug-delivery system (DDS) carriers for combination therapy is required. The ideal DDS carrier for combination therapy should itself have antitumor activity in addition to the ability to deliver drugs to tumors. α-Tocopheryl succinate (TS), a succinic acid ester of α-tocopherol, has attracted attention as a unique antitumor agent, and TS itself can form nanoparticles. In this review, we introduce nanoparticles consisting of TS as a novel DDS carrier with multifaceted antitumor effects for combination therapy.