The paper presents the first results of a dark matter search using the WINERED spectrograph installed on the 6.5m Magellan Clay telescope. The authors aimed to detect dark matter decaying into line photons with masses around 1.8–2.7 eV by observing dwarf spheroidal galaxies (dSphs) Leo V and Tucana II. They employed a nodding observation technique to subtract background noise and established stringent limits on the dark matter decay rate. The data can also be used to constrain other photon-producing processes. The analysis considered both spectrum-independent and line-subtraction methods, providing robust constraints on dark matter decay rates. The study highlights the potential of WINERED for future dark matter searches and complements previous studies using other instruments.The paper presents the first results of a dark matter search using the WINERED spectrograph installed on the 6.5m Magellan Clay telescope. The authors aimed to detect dark matter decaying into line photons with masses around 1.8–2.7 eV by observing dwarf spheroidal galaxies (dSphs) Leo V and Tucana II. They employed a nodding observation technique to subtract background noise and established stringent limits on the dark matter decay rate. The data can also be used to constrain other photon-producing processes. The analysis considered both spectrum-independent and line-subtraction methods, providing robust constraints on dark matter decay rates. The study highlights the potential of WINERED for future dark matter searches and complements previous studies using other instruments.