We propose to undertake an unprecedented, in-depth, and unique study of star and planet formation in the Ophiuchus star forming region over a period of 15 nights on Gemini South with the IGRINS infrared spectrograph. A single IGRINS exposure yields 43 gap-free orders at resolution 45,000, covering from 1.45 to 2.5 μm; this broad, simultaneous wavelength range provides hundreds of photospheric absorption lines with which to measure surface gravity, effective temperature, and magnetic field strength. Broad spectral coverage also enables the measurement of the accretion rate and veiling as a function of wavelength and secondary stellar parameters like rotation speed (modulo inclination), radial velocity, and binarity for close binaries. The power of this project lies in our ability to measure this entire suite of fundamental properties simultaneously for the first time using the same technique for objects from the first emergence of a photosphere through to the ZAMS, providing the most profound insight into a young star + circumstellar disk population ever realized. At Gemini South we will focus on the youngest, most embedded, lowest mass, and hence faintest, component of our comprehensive sample. With our sample and precise physical parameters we will answer fundamental questions about the initial conditions of star formation (including accretion, magnetic fields, and star/disk interactions), which define the form of the IMF and the survival of planetary systems.