The properties of low-mass galaxies hosting central black holes provide clues about the formation and evolution of the progenitors of supermassive black holes. In this letter, we present HSC-XD 52, a spectroscopically confirmed low-mass active galactic nucleus (AGN) at an intermediate redshift of $zsim0.56$. We detect this object as a very luminous X-ray source coincident with a galaxy observed by the Hyper Suprime-Cam (HSC) as part of a broader search for low-mass AGN. We constrain its stellar mass through spectral energy distribution modeling to be LMC-like at $M_star approx 3 times 10^9 M_odot$, placing it in the dwarf regime. We estimate a central black hole mass of $M_mathrm{BH} sim 10^{6} M_odot$. With an average X-ray luminosity of $L_X approx 3.5 times 10^{43}~mathrm{erg}~mathrm{s}^{-1}$, HSC-XD 52 is among the most luminous X-ray selected AGN in dwarf galaxies. The spectroscopic and photometric properties of HSC-XD 52 indicate that it is an intermediate redshift counterpart to local low-mass AGN.
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